A lens barrel is provided that includes a base, a motor, a drive gear, and a rotary frame. The motor is fixed to the base and produces a driving force. The drive gear is coupled to the base and configured to transmit the driving force. The rotary frame has a substantially cylindrical shape and a gear component disposed on at least part of its inner peripheral surface. The gear component meshes with the drive gear so that during rotation of the drive gear the rotary frame rotates, via the driving force, relative to the base component and advances and retracts along a rotational axis of the lens barrel. The length of the drive gear is greater than the length of the gear component, and as the rotary frame and the gear component advance and retract, the gear component remains within a range of opposing ends of the drive gear.