Abstract: A clutch generating stress equally at a plurality of bridges parts of a driving side clutch plate to thereby prevent bridge parts from breaking easily during transmission of drive power, wherein a plurality of hole parts 13c and 13d are formed, arranged in a circumferential direction, respectively at the outer circumference side and inner circumference side of a driving side clutch plate 13b, and bridge parts 13e and 13f are formed adjacent in a circumferential direction between the hole parts 13c and 13d, the driving side clutch plate 13b comprises a friction surface 13a pressed to the driven side clutch plate 18 and an opposite friction surface 13h on the opposite side of the friction surface, and a thickness t1 of the inner circumference side is greater than a thickness t2 of the outer circumference side of the same with respect to the plate thickness between the friction surface 13a and the opposite friction surface 13h.