A manufacturing method of an endless metal belt having metal rings built up and differing in circumference, includes the following steps of: a first circumference correction step of expanding each of the metal rings; and a second circumference correction step of expanding each of the metal rings after conducting a solution heat treatment to the expanded metal ring. In the manufacturing method, by executing the first circumference correction step and the second circumference correction step before and after the solution heat treatment, respectively, an expansion quantity for setting a circumference of each of the metal rings to become a predetermined length is attained.