The world’s oldest continuously running family owned business is temple construction firm Kongo Gumi. The Japanese company was founded in the 6th century A.D. (578 A.D.) and is currently run by the 40th generation of the family.
Historical Precedence
Prince Shotoku brought Kongo family members to Japan from Korea more than 1,400 years ago to build the Buddhist Shitennoji Temple, which still stands. Over the centuries, Kongo Gumi has participated in the construction of many famous buildings, including the 16th-century Osaka castle. Today the family continues to build and repair religious temples and manage general contracting from its Osaka headquarters.
http://www.kongogumi.co.jp