To provide a thumb-turn device capable of smoothly changing a mode.

This thumb-turn device is exposed to the indoor side, and performs locking-unlocking operation of a door lock device by operation to a rotary operation body 2 free in rotary operation to a housing 1. The thumb-turn device has a clutch part 4 interposed between the rotary operation body 2 and a joint 3 connected to the lock device and connecting-disconnecting the transmission to the joint 3 of rotary operation force to the rotary operation body 2, and a mode selecting part for moving and holding the clutch part 4 in a connecting-disconnecting state by being driven independently of the joint 3 in operation.