To solve problems that the deterioration of sealability, the damage of a bearing and the cost-up in a rotating transmitting device.

In this rotating transmitting device composing a clutch for engaging and disengaging an inner member 1 and an outer member 2 by changing a phase of a cage 5 holding an engager 6 to the inner member 1 or the outer member 2, a sealing device 20 mounted between a housing 4 and at least one of the inner member 1 and the outer member 2 is inwardly recessed from an end face of the housing 4 to improve the sealability. The cost can be reduced by eliminating a bearing seal member 3d of a bearing 3 mounted at a side opposite to an opening side of the housing 4, and the damage of the bearing is prevented by regulating a fastening margin of the bearing 3 and the outer member 2 to determine the contact stress on a center of a contact part of an inner ring 3a and a rolling element 3c of the bearing 3 to 4200 MPa or less which is a standard numerical value in designing of the bearing.