山口工業株式会社

What 山口工業株式会社 does

山口工業株式会社 (Yamaguchi Kogyo Co., Ltd.) is a privately-held Japanese construction company founded in April 1990 and incorporated on July 1, 2009, headquartered in Nagoya (Minami-ku, Aichi Prefecture) with a Toyoake sales office. The firm operates six integrated service lines: building construction (ALC exterior walls, multi-level parking structures, monuments); temporary scaffolding and false work; civil engineering (revetments and soundproof walls); equipment installation (ductwork, machinery relocation); solar panel installation (parking wall-mounts, factory rooftops, ground, and slope settings); and electromagnetic-radar nondestructive testing of concrete structures — detecting rebar, PC steel wires, vinyl pipes, and cables at depths up to 300mm.

The business runs a project-based B2B contracting model, generating revenue through one-time construction and engineering service fees with quote-based, non-public pricing. It maintains 11 Japanese construction business licenses spanning civil, scaffolding, stone, plumbing, steel structures, paving, sheet metal, painting, machinery installation, water facilities, and demolition trades. A network of more than 35 cooperative partner companies — covering equipment rental, scaffolding, concrete, electrical, steel, and specialty trades — allows the firm to scale delivery beyond its core 5-person headcount. Sales are driven through direct website inquiries, phone, and inbound contacts, with no formal marketing motion beyond a corporate website and social-share functionality.

Customers are enterprise general contractors, infrastructure operators, and public-sector entities, primarily in the Chubu region. The published client roster includes Kinden, JFE Engineering, JFE Civil, Chubu Centrair International Airport, Taisei Komuto, Taiyu Kensetsu, Japan Construction, Nippon Facility, Nagoya Prison, and Kitagawa Tekkosho. The company states it also accepts projects outside Aichi Prefecture, indicating modest national scope. Leadership comprises Representative Director and President Yamaguchi Takahiro and Managing Director Goto Toshimitsu, with no external investors, parent company, or public listing.

Name

山口工業株式会社

Legal name

山口工業株式会社

Website

https://yg-k.jp

Company type

Private

Founded year

1990

Operating status

Operating

Headcount range

1–10 employees

Short description

Privately-held Japanese construction firm based in Nagoya, Aichi Prefecture, offering six integrated service lines — building, civil, scaffolding, equipment, solar panel installation, and electromagnetic-radar nondestructive concrete testing — to general contractors, infrastructure operators, and public-sector clients across the Chubu region.

Ownership category

akta.pro rank

Product category

Construction Services

NAICS

Engineering Services (541330), Testing Laboratories and Services (54138), Building Inspection Services (54135)

SIC

Construction - Special Trade Contractors (1700), Services-Testing Laboratories (8734)

akta.pro primary industry

Insulation, Scaffolding & Access Services (ISA) (IMAIACAF)

Keywords

• Construction subcontracting
• Nondestructive testing
• Civil engineering
• Building construction
• Solar panel installation

Headquarters

HQ city

Nagoya

HQ country

Japan

HQ region

Asia

Offices2 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Supply Chain, Operations, Technology or R&D, Marketing or Sales

Revenue model

1. Construction and Engineering Services: The company generates revenue through civil engineering, building construction, temporary works, equipment installation, and solar panel installation projects. Revenue is earned through project-based contracting and construction service fees.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels3 records

Core offering

山口工業株式会社 is a construction services company that performs building construction, civil engineering, temporary scaffolding and false work, equipment installation (ducts and machinery relocation), and solar panel installation under project-based contracts. In parallel, the company delivers a specialized electromagnetic-wave radar nondestructive testing service that detects buried objects, rebar, PC steel wires, vinyl pipes, and cables inside concrete structures (up to 300mm depth) to support safe drilling, coring, and structural inspection. Services are sold primarily to general contractors, civil engineering firms, and infrastructure operators in the Chubu region of Japan.

Product overview

Yamaguchi Kogyo Co., Ltd. is a construction company offering a portfolio of specialized construction and inspection services. The company operates six core service lines: non-destructive testing (using electromagnetic wave radar technology for detecting buried objects and structural elements), building construction (including ALC exterior walls and parking structures), temporary scaffolding work, civil engineering (revetments and sound barriers), equipment installation (ducts and machinery relocation), and solar panel installation. These services are designed for industrial, commercial, and infrastructure clients primarily in Aichi Prefecture and surrounding regions.

Differentiator

Problem solved

Functional benefit

Products and services

• Non-Destructive Testing (非破壊検査) Electromagnetic-wave radar inspection service that detects buried objects, rebar, PC steel wires, vinyl pipes, and cables inside concrete structures, with capability to measure concrete cover thickness, wall thickness, slab thickness, and rebar arrangement up to a maximum detection depth of 300mm. Used by general contractors, civil engineering firms, and infrastructure operators to avoid striking hidden elements during drilling or coring.
• Building Construction (建築工事) Building construction services including ALC exterior wall construction, multi-level parking structures, and monument construction work, delivered to commercial and infrastructure clients primarily in Aichi Prefecture.
• Temporary Construction (仮設工事) Temporary scaffolding and false work services including external wall scaffolding and elevated/under-bridge suspended scaffolding, provided to construction sites primarily in Aichi Prefecture.
• Civil Engineering (土木工事) Civil engineering construction services including revetment/retaining wall construction and soundproof wall construction, delivered to general contractors and infrastructure operators in Japan.
• Equipment Installation (設備工事) Equipment installation services including duct work and machinery relocation/installation for industrial and commercial clients.
• Solar Panel Installation (ソーラーパネル工事) Solar panel installation services for multi-level parking wall-mounted installations, factory rooftop installations, ground installations, and slope installations.

Named customers10 records

Segments2 records

Ideal customer profiles1 record

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature1 record

Partnerships

Six partnerships are on record, tiered minor and core.

• 株式会社アクティオminorOthersConstruction equipment rental partner. Listed as a major partner company among the company's cooperative partner network. Provides rental equipment for construction projects.
• 株式会社安藤組minorOthersScaffolding work subcontractor partner. Listed as a major cooperative partner company.
• 大有建設株式会社coreStrategic or Co-development PartnerListed as a major client (主な取引先). Major civil engineering construction company that engages Yamaguchi Kogyo for specialized construction and nondestructive testing services.
• 株式会社きんでんcoreStrategic or Co-development PartnerListed as a major client (主な取引先). Major electrical construction company that engages Yamaguchi Kogyo for specialized construction and nondestructive testing services.
• 中部国際空港株式会社coreStrategic or Co-development PartnerListed as a major client (主な取引先). Chubu Centrair International Airport operator that engages Yamaguchi Kogyo for specialized construction and nondestructive testing services.
• 奥地建産株式会社coreStrategic or Co-development PartnerListed as a major client (主な取引先). Major construction materials and civil engineering company that engages Yamaguchi Kogyo for specialized construction and nondestructive testing services.

Scale indicators4 records

Recent moves6 records

Expansion highlights5 records

Direct peers

• Matsui Construction: Small-to-mid Japanese general contractor offering building construction, civil engineering, and equipment installation across multiple trades. Comparable to Yamaguchi Kogyo in its multi-trade orientation, Japanese private-company structure, and reliance on subcontractor execution for capacity.
• SUGITAKA: Japanese company specializing in scaffolding and temporary works services, including rental and installation. Directly comparable to one of Yamaguchi Kogyo's core service lines (仮設工事 / temporary scaffolding), serving similar construction-industry customers with adjacent access solutions.

Broad incumbents

• Okumura Corporation: Established Japanese general contractor with strong civil engineering and temporary-works capabilities. Overlaps with Yamaguchi Kogyo's scaffolding and civil service lines, but operates at significantly larger scale across broader geographies as a long-tenured incumbent.
• KAJIMA Corporation: One of Japan's largest general contractors with broad civil, building, equipment, and infrastructure capabilities. Operates as a broad incumbent in the same overall space as Yamaguchi Kogyo but at vastly larger scale, providing context on the competitive landscape for multi-trade Japanese contractors.

Regional players

• Yahagi Construction Industry: Mid-size Japanese general contractor headquartered in Aichi Prefecture offering civil engineering, building construction, and equipment installation. Closely comparable to Yamaguchi Kogyo in regional footprint, multi-trade orientation, and client base of industrial and infrastructure operators in the Chubu region.
• Meiko Construction: Mid-size Japanese general contractor based in Nagoya/Aichi providing civil engineering, building construction, and equipment work. Comparable in scale, regional focus, and multi-trade offering to Yamaguchi Kogyo, with similar customer mix of industrial and infrastructure clients in the Chubu region.

Market position

Strengths4 records

Weaknesses5 records

Competitive moat3 records

Key risks5 records

Key highlights5 records

Customer concentration

• LinkedInlinkedin.com/company/%E5%B1%B1%E5%8F%A3%E5%B7%A5%E6%A5%AD%E6%A0%AA%E5%BC%8F%E4%BC%9A%E7%A4%BE

Revenue estimate

Valuation estimate

Number of profiles

Profiles2 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about 山口工業株式会社