A lens barrel including a telescopic cylinder accommodated within a fixed cylinder and lenses, the lens barrel having lens retaining frames and a lens driving device which drives the telescopic cylinder between a collapsed position and an extended position, wherein the lens barrel further includes a retractable lens that is retracted into the fixed cylinder through an opening in a wall of the fixed cylinder when the telescopic cylinder is in the extended position, a retractable lens retaining frame therefor and an impact preventing member, and wherein if the lenses are in the extended position and an external impact is received by the lens barrel, the impact preventing member abuts against one of the lens retaining frames to prevent the lens retaining frames from moving to the collapsed state.