The present invention makes it possible to simplify a structure in a transmission that transmits the power of an electric motor.In a transmission including: a transmission shaft 21 driven by an electric motor 14； and a case 23 that supports the electric motor 14 and the transmission shaft 21, the transmission including an adapter 24 which is interposed between the case 23 and the electric motor 14 and to which the electric motor 14 is attached, the adapter 24 is in contact with one end 27a of the transmission shaft 21 in an axial direction of the transmission shaft 21.
