A clutch mechanism includes a first and a second rotating members, a clutch hub, a clutch drum, a plurality of friction engagement elements, a piston, a piston driving device and a sleeve. A clutch hub main body of the clutch hub is connected to the first rotating member and does not rotate relative to the first rotating member. An inner hub of the clutch hub rotates relative to the clutch hub main body. The inner hub engages with an inner peripheral side of the friction engagement elements and does not rotate relative to the friction engagement elements. The sleeve does not rotate relative to the inner hub. The sleeve moves relative to the first rotating member. The sleeve moves in conjunction with the piston to a position where the sleeve engages with the clutch hub main body and does not rotate relative to the clutch hub main body.