A cylinder tube of a second hydraulic cylinder is provided separate from a first piston of a first hydraulic cylinder and integrally fixed to an input shaft. Friction members of a first clutch and friction members of a second clutch are prevented from moving in a first direction by a snap ring attached to a connecting drum. The friction members of the first clutch are friction engaged by the first piston and the friction members of the second clutch are friction engaged by a second piston.