A rotating device includes a motor, a gear, and a housing configured to accommodate the motor and the gear. The housing includes a first housing, a second housing, and a joining element for joining the first housing and the second housing. The first housing includes a first attaching part attached to an external device. The second housing includes a second attaching part attached to the external device. The first attaching part and the second attaching part include surfaces opposing each other after the housing is assembled. The first attaching part and the second attaching part include the joining element.