Frictional engagement elements (561) of a first hydraulic clutch (C1) and frictional engagement elements (562) of a second hydraulic clutch (C2) are supported on a common clutch drum (42) on opposite sides of a snap ring (55). Openings are defined respectively in the clutch drum and an urging member (462) which is formed integrally with a clutch piston (442) of the second hydraulic clutch for urging the frictional engagement elements toward the snap ring. An urging member for urging (461) the frictional engage elements toward the snap ring is connected to a clutch piston (441) of the first hydraulic clutch and extends through the openings to the outside of the clutch drum. Thus, the pair of hydraulic clutches disposed in a tandem fashion can be operated stably without interference from each other. <IMAGE>
