Even if programs or data written to storage devices of electronic control units incorporated in automatic transmissions are different for each of the specifications of vehicles mounted with the automatic transmissions, the electronic control units can be distinguished only by means of the difference between the hardware configurations and managed. Disclosed is a method for manufacturing an automatic transmission, which comprises an assembly process (10) for the automatic transmission that includes the incorporation of an electronic control unit, and a test process (30) for the automatic transmission, the assembly of which has been completed by the assembly process (10), wherein a write process (20) for writing vehicle correspondence information consisting of a program and/or data corresponding to the specification of a vehicle mounted with the automatic transmission to a storage device of the electronic control unit incorporated in the automatic transmission is executed after the assembly process (10), and before the test process (30).