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Message From the President

To evolve into a company that will last 100 years for the next 50 years
– Aspirations and beliefs for heights, and its pride as an expert in shaping buildings and towns –

ACA SEKKEI celebrated its 50th anniversary in July 2020. Since its founding in 1970, it has always inherited the stance of taking on challenges. With awareness and pride as a group of architectural design specialists, we have contributed widely to society through our design activities, aiming for attractive architecture that is trusted and pleased by our clients.
We will respond to the changing sophistication and complexity of society, pursue new technologies with aiming for highly worth design work. We will pursue “architecture in the environment” that is harmonized with the natural environment and local communities and create architecture that contributes to the creation of a sustainable society.
As construction demand is declining due to today’s declining birthrate and aging society, we will focus on already opened bases in Southeast Asia, where development is expected in domestic local cities and future development, and always challenge undeveloped areas with foresight. We will continue to develop and grow into a company that can meet all social needs and create new value to further refine and evolve our efforts so far and make a further leap forward in the next 50 years.
Yoshinori Kobayashi, President

Company Profile

Address Name First-Class Registered Architect Office
Registration Nagano Head office
Registered by Governor of Nagano Prefecture (Register No. M77312)
Management Architect : Hidekuni Tatsuno
Tokyo Branch
Registered by Governor of Tokyo Metropolitan (Register No. 53789)
Management Architect : Kouji Sato
Establishment July 15 , 1970
Capital 40,000,000 yen
Employees 100(male 77, female 23)
(Total members of ACA Group 142)
Qualified Employees Registered Japan 1st-Class Architects/Engineers : 45
Building services architects : 3
Quantity surveyors : 9
In charge of structure : 8
In charge of mechanical and electrical design : 13

Scope of Services

ACA SEKKEI Organization Chart

Branch/Overseas Office

Nagano head office 2360-4 Yanagihara, Nagano City, Nagano 381-0012, Japan
TEL. +81-26-296-8300 FAX. +81-26-296-8350・・・MAP
Tokyo branch office PMO-Kanda-Manseibashi Bldg.4F, 1-3-9 Kandasudacho, Chiyoda-ku,Tokyo 101-0041, Japan
TEL. +81-3-5297-8177 FAX. +81-3-5297-8176・・・MAP
Matsumoto branch office 2-8-10 Soyano, Matsumoto City, Nagano 390-0842, Japan
TEL. +81-263-88-2224 FAX. +81-263-88-2237・・・MAP
Joetsu branch office 4-3-19 Nakamachi, Joetsu City, Niigata 943-0831, Japan
TEL. +81-25-530-7130 FAX. +81-25-530-7137・・・MAP
Ho Chi Minh Office 12F – Havana Tower, 132 Ham Nghi Street, Ben Thanh Ward, District1,Ho Chi Minh City, Viet Nam
TEL. +84-8-3821-2332・・・MAP
Yangon Office No.0204, Sakura Tower, 339 Bogyoke Aung San Road, Kyauktada Township, Yangon, Myanmar
TEL. +95-1-255217・・・MAP


1999 change of the company’s name to ACA SEKKEI CO., LTD
2001 ISO9001 certification
2005 Participation in PFI projects
2006 Establishment of ACA TOSHIKIKAKU CO., LTD
2007 Establishment of the Tokyo branch office
2008 SANYU Facilities Design CO., LTD participates in ACA GROUP
2011 Transfer of management rights to ACA TOSHIKIKAKU CO., LTD
2012 Establishment of the Ho Chi Minh Office
Establishment of ACA KENBI CO., LTD
2013 Establishment of the Yangon Office
Establishment of the ACA CONSULTING CO., LTD
2014 Establishment of the Matsumoto branch office and the Joetsu branch office
Agreement conclusion with DESIGN 2000 CO., LTD
Establishment of the ACA Architectural Inspection CO., LTD
2018 Merging SANYU Facilities Design CO., LTD and ACA SEKKEI MATSUMOTO CO., LTD
2020 50th anniversary

Major Affiliated Organizations

・The Japan Institute of Healthcare Architecture
・The Architectural Institute of Japan
・The Japan Structural Consultants Association
・The society of Heating, Air-Conditioning and Sanitary Engineers of Japan
・The Urban Renewal Association of Japan
・Nagano Association of Architectural Firm
・The Nagano Building Disaster Prevention Association
・The Nagano Chamber of Commerce and Industry
・Tokyo Association of Architectural Firms
・The Japanese Business Association of Ho Chi Minh City
・Japan Chamber of Commerce and Industry, Myanmar


Executive officers
Chief Operating Officer
Vice President
Managing Executive Officer
Managing Executive Officer
Executive Officer
General Manager of Tokyo Branch
Executive Officer
Executive Officer
Executive Officer
Executive Officer
Yoshinori Kobayashi
Registered Japan 1st- Class Architect
Keiji Yumoto
Registered Japan 1st- Class Architect
Yoshio Sakamoto
Registered Japan 1st- Class Architect
Keiichi Sekizaki
Kouji Sato
Registered Japan 1st- Class Architect
Tsutomu Kaise
Registered Japan 1st- Class Architect
Kakihisa Baba
Registered Japan 1st- Class Architect
Jinichi Kasuga
Registered Japan 1st- Class Architect
Susumu Tokutake
Member of the Board
Representative Director
Taiichi Tatsuno
Registered Japan 1st- Class Architect
Namio Sekiguchi
Registered Japan 1st- Class Architect
Yoshinori Kobayashi
Registered Japan 1st- Class Architect
Keiji Yumoto
Registered Japan 1st- Class Architect
Senior Adviser
Hidekuni Tatsuno
Registered Japan 1st- Class Architect