To install a parking mechanism in a large freedom degree around an output gear in an automatic transmission dividing transmission components into two and disposed with the output gear between them.

A first transmission component (second clutch 70) is disposed in the front side of an intermediate partition wall 195 formed in a transmission case 180, an output gear 170 is rotatably supported in its rear side, and a second transmission component is disposed in the rear side of the output gear 170. An internal gear 171 connected to the output gear 170 is formed with a parking gear 504 and a parking pole 503 facing thereto is disposed in a slitting 50 formed in a support part 194c of the transmission case 180, the parking pole is rotationally supported to a parking pole shaft 502 extending rearward from the front end of the support part 194b, and a return spring 506 is wound around a part projecting from the support part 194b of the parking pole shaft 502.