Transmission

To provide a transmission capable of using generator/motors of smaller maximum torque and of small size. The transmission includes input shaft (4), output shaft (16), a mechanical transmission part interposed between input shaft (4) and output shaft (16) including planetary gear mechanisms (5), (6), and an electric transmission part interposed between input shaft (4) and output shaft (16) including three generator/motors (21A), (25A), (31 A). A rotating shaft of first generator/motor (21A) and a rotating shaft of the second generator/motor (25A) are respectively coupled to the mechanical transmission part. Clutches (34), (35), (36) are provided for coupling a rotating shaft of third generator/motor (31A) to at least one of the rotating shaft of first generator/motor (21A) and the rotating shaft of second generator/motor (25A).