A lens barrel comprises a lens moving member rotatable about the optical axis of the lens barrel for axially moving a focusing lens group, a manual operation member for manually rotating the lens moving member, an ultrasonic wave motor including of a stator composed of piezoelectric members and an elastic member, and a rotor rotating about the optical axis and maintained in pressure contact with the stator, a mode switching member for selecting either a first focusing mode for effecting focusing by driving the lens moving member by the ultrasonic wave motor, or a second focusing mode for effecting focusing by rotating the lens moving member with the manual operation member, and a clutch member engaged for transmitting the rotation of the rotor to the lens moving member without change in the contact pressure of the rotor with the stator in response to the switching to the first focusing mode by the mode switching member, and disengaged in response to the switching to the second focusing mode.