There is disclosed a lens barrel including a fixed frame, a rotary frame
rotatable with respect to the fixed frame to advance or retract in an
optical axis direction, and a rectilinear guide frame rotatable relative
to the rotary frame to displace integrally with the rotary frame in the
optical axis direction. In this structure, a front end portion of the
rectilinear guide frame on a subject side in the optical axis direction
is exposed from the rotary frame.