Abstract:The internal mechanisms of KARAKURI dolls of Edo era, that realize complicated motions of KARAKURI dolls, include the fundamental mechanisms which are common in Western modern mechanisms. In this research, the machine technology of Japan of those days was analyzed by comparing the mechanism of KARAKURI dolls with Reuleaux models which are considered to be the Western modern typical fundamental machine mechanisms. The mechanisms of KARAKURI dolls were referred to the machine technical document "KARAKURI-ZUI" of the Edo era.