A second clutch piston formed of a plurality of members including a cylindrical cylinder member, a disc-shaped bottom plate member that fits in one end portion of that cylinder member, and a snap ring, has a plurality of long positioning protrusions provided on an inner peripheral surface of the cylinder member. By abutting the disc-shaped bottom plate member against end surfaces of these positioning protrusions, the bottom plate member can be fit into the one end portion of the cylinder member without having to provide notches therein, which enables durability against a pulling force generated in the cylinder member when the friction apply device is applied to be maintained.