共栄産業株式会社

What 共栄産業株式会社 does

共栄産業株式会社 (Kyoei Sangyo Co., Ltd.) is a Yokohama-headquartered specialty construction contractor providing integrated facility equipment services across five core disciplines: water supply and drainage/sanitary equipment, air conditioning and ventilation, fire extinguishing systems, refrigeration equipment, and water distribution pipe construction. Established in 1959 as a limited company and reorganized as a corporation in 1960, the firm holds Kanagawa Prefecture Special and General Construction Permits (No. 6825) and operates with ISO 9001 and ISO 14001 certifications, qualifying it for public-sector construction contracts. The company serves two primary customer segments: government and quasi-government clients (notably Yokohama City, Kanagawa Prefecture, and Yokohama City Maintenance Corporation) accessed through competitive tendering, and private general contractors (including 南海辰村建設, 東亜建設工業, 多田建設, and 小俣組) accessed through direct field sales for subcontracting work.

The business model is project-based and entirely direct, with no intermediary or reseller channels. Revenue is recognized as one-time project revenue, fluctuating with the timing and size of completed construction projects. The firm reported ¥853M in revenue for FY2025/2026, down from a FY2022 peak of ¥1,005M, with the YoY swings typical of project-based contractors. All operations are concentrated in Kanagawa Prefecture and Tokyo. The company operates with a lean staff of 19 employees across three departments (Construction, Sales, and General Affairs), reflecting a tight overhead structure suited to its regional specialty contracting niche.

Since August 2017, the company has operated as an affiliate of Shinko Holdings Group, a diversified construction and equipment holdings group, providing organizational backing and cross-referral potential. The current representative director, Yoshida Kotaro, was appointed in September 2017 coinciding with the group affiliation. The company's competitive position rests on its regulatory credentials, 65+ years of operating history, repeated Yokohama Regional Contribution Enterprise recognition, and established direct relationships with regional government and major construction firms. No technology platform, software products, AI capabilities, or external funding are present; the business is a traditional skilled-trades operation with modest recurring investment in community engagement (Yokohama FC sponsorship since 2014) and a refreshed corporate website (July 2025).

Name

共栄産業株式会社

Legal name

共栄産業株式会社

Website

https://nksc.jp

Company type

Private

Founded year

1960

Operating status

Operating

Headcount range

1–10 employees

Short description

共栄産業株式会社 is a Yokohama-based specialty construction contractor providing plumbing, HVAC, fire protection, refrigeration, and water distribution pipe installation services to government entities and private construction firms across Kanagawa Prefecture and Tokyo, operating as a Shinko Holdings affiliate with 19 employees.

Ownership category

akta.pro rank

Product category

Facility Equipment Construction Services

NAICS

Plumbing, Heating, and Air-Conditioning Contractors (238220)

SIC

Construction - Special Trade Contractors (1700), Water, Sewer, Pipeline, Comm & Power Line Construction (1623)

akta.pro primary industry

HVAC & Refrigeration Contracting (IMAFALAB)

Keywords

• Plumbing construction services
• HVAC installation
• Fire protection systems
• Water distribution infrastructure
• Refrigeration equipment installation

Headquarters

HQ city

Yokohama

HQ country

Japan

HQ region

Asia

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Supply Chain, Operations, Marketing or Sales, Infrastructure, Others

Revenue model

1. Construction Services Revenue: Project-based revenue from pipefitting construction projects including plumbing/sanitation, HVAC, fire protection, refrigeration, and water distribution systems. Revenue fluctuates significantly year-over-year, ranging from approximately ¥257M (6-month period in FY2021) to over ¥1B in FY2022, reflecting project-based nature.

Go-to-market motion2 records

Distribution channels2 records

Marketing channels3 records

Core offering

共栄産業株式会社 (Kyoei Sangyo Co., Ltd.) is a facility equipment construction contractor providing five core services: water supply/drainage and sanitary equipment construction, air conditioning and ventilation equipment construction, fire extinguishing equipment construction, refrigeration equipment construction, and water distribution pipe construction. The company serves government entities and private construction companies in Kanagawa Prefecture and Tokyo, managing projects from planning through installation and maintenance. As a subsidiary of Shinko Holdings Group and a specialized contractor, it delivers both new installations and renovation work for residential, commercial, and public facilities.

Product overview

共栄産業株式会社 is a comprehensive facility equipment company offering integrated plumbing and equipment construction services. The company operates three departments—Construction, Sales, and General Affairs—providing five core construction services: water supply/drainage and sanitary equipment, air conditioning and ventilation, fire extinguishing systems, refrigeration equipment, and water distribution pipe construction. All services are focused in Kanagawa Prefecture and Tokyo, with the company operating as a specialized contractor under the Shinko Holdings Group.

Differentiator

Problem solved

Functional benefit

Products and services

• Water Supply/Drainage and Sanitary Equipment Construction (給排水・衛生設備工事) Construction management for water supply, drainage, and sanitary piping systems for buildings, including fixtures such as toilets and baths. Focuses on resource conservation and efficient management for buildings in the Kanagawa/Tokyo area.
• Air Conditioning and Ventilation Equipment Construction (空調・換気設備工事) Construction management for air conditioning and ventilation systems and associated piping. Manages humidity, moisture, and airflow to maintain comfortable living and working spaces in residential and commercial buildings.
• Fire Extinguishing Equipment Construction (消火設備工事) Installation and construction management of fire extinguishing equipment and piping as mandated by fire protection laws. Ensures equipment is always ready for rapid use in emergencies for buildings and facilities.
• Refrigeration Equipment Construction (冷凍設備工事) Design, installation, and maintenance of refrigeration equipment for food storage facilities. Supports essential infrastructure for daily life and food cold chain operations.
• Water Distribution Pipe Construction (配水管工事) Construction management for water distribution pipes that supply clean water from purification facilities to homes and facilities. Manages underground pipe infrastructure ensuring safe, clean water supply for municipal and private water systems.

Named customers7 records

Segments2 records

Ideal customer profiles2 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Partnerships

Seven partnerships are on record, tiered core and minor.

• シンコーホールディングス (Shinko Holdings)coreStrategic or Co-development Partner · 1 August 2017Joined Shinko Holdings group in August 2017. This is a significant corporate group affiliation that provides the company with organizational backing and potential synergies across the holdings group. A link to Shinko Holdings website is maintained on the company website.
• 岡部バルブ工業株式会社minorOthersListed as a major supplier of valve products and materials used in plumbing and piping construction projects.
• 渡辺パイプ株式会社minorOthersListed as a major supplier of piping materials and equipment for construction projects.
• 日本管材センター株式会社minorOthersListed as a major supplier of piping materials and plumbing equipment.
• 横浜信用金庫minorOthersOne of three listed transaction banks, providing banking services and financial support for the company's operations.
• 横浜銀行minorOthersOne of three listed transaction banks, providing banking services for the company's operations.
• 三井住友銀行minorOthersOne of three listed transaction banks, providing banking services for the company's operations.

Scale indicators7 records

Recent moves10 records

Expansion highlights4 records

Market position

Competitive moat4 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/%E5%85%B1%E6%A0%84%E7%94%A3%E6%A5%AD%E6%A0%AA%E5%BC%8F%E4%BC%9A%E7%A4%BE

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

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 共栄産業株式会社