SEATBACK ROTATING DEVICE

Provided is a seatback rotating device used for a vehicle seat. The seatback rotating device includes an electric motor, an action mechanism, a rotor, and an abutment target portion. In the seatback rotating device, when s seatback of the vehicle sat is placed in a first standing position, the rotor is positioned in a standby state that creates a gap between a first protrusion and the abutment target portion and a gap between a second protrusion and the abutment target portion, the first protrusion and the second protrusion being provided to the rotor. In the standby state, a gap length from the first protrusion to the abutment target portion is small relative to a gap length from the second protrusion to the abutment target portion.