To prevent the wear of components of a hydraulic clutch.

One end of a return spring 47 is locked to a clutch piston 44, and the other end of the return spring 47 is fixed to a spring seat 46. The spring seat 46 is supported in an axial direction by a cancel plate 45. In addition, protrusions 450 protruding in the radial direction are formed in the cancel plate 45, and recesses 460 engageable with the protrusions 450 are formed in the spring seat 46.