PURPOSE: To aim at improving the durability, the life and the transmission efficiency of a first clutch shoes by providing second clutch shoes for lock-up at the time of very high speed rotation on the input side and recessed parts for lock-up fitted with the second clutch shoes on the output member side.

CONSTITUTION: Through holes 20, 21 are bored in first clutch shoes 11, 12 pivotally fixed at an input member 10 and provided with a tension spring, and second clutch shoes 18, 19 are inserted into through holes 20, 21 as well as compression springs 24, 25 are interposingly mounted between the flange formed head parts 22, 23 of the second clutch shoes 18, 19 and the first clutch shoes 11, 12. In addition, recessed parts 26-29 corresponding to the tips 30, 31 of the second clutch shoes 18, 19 in the form are provided at the drum inner peripheral surface 17 of an output member 16. Accordingly, sliding is not generated even in the region of high or very high speed rotation, and the durability, the life and the transmission efficiency of the first clutch shoes 11, 12 are improved.