PURPOSE: To reduce drag torque at the lock-up non-operated time by providing elastic members for separating plural friction parts from one another at the non-operated time of a device.

CONSTITUTION: A front cover 1 is provided integrally with numerous engaging protrusions 18 disposed at circumferentially equal spaces apart on the inner peripheral surface of an outer peripheral wall 1a in such a way as to be parallel with a centerline O-O, and the inner peripheral part of a snap ring 19 fixed to the rear end of the engaging protrusion 18 can be brought into contact with a plate 17 to regulate the backward movement of the plate 17. On the outer peripheral side of a supporting member 21, an annular wave spring 22 is disposed between a piston 12 and a disk 20. In the clutch disconnected state, the disc 20 and the plate 17 are both regulated in their movement onto the piston 12 side respectively by the wave spring 22 and the snap ring 19, so that gaps can be secured positively among the disk 20, plate 17 and piston 12.