A lens barrel includes a) a plurality of lens groups each having at least one lens, b) a plurality of lens retaining frames, including a retractable lens retaining frame, c) lens retaining frame driving devices, d) a main-guide shaft member in parallel to the optical axis to support the retractable lens retaining frame rotatably in longitudinal and circumferential directions of the main-guide shaft member, and e) a sub-guide shaft member to guide the retractable lens retaining frame along the optical axis and to allow the retractable lens retaining frame to be retracted toward the retracted position at a retracting point on the main-guide shaft member and to guide the retractable lens retaining frame on the main-guide shaft member along the optical axis at other than the retracting point. The retractable lens retaining frame is formed with an engaging portion to engage with the sub-guide shaft member and to be guided along the sub-guide shaft member, and the engaging portion being formed with an opened portion configured to allow the retractable lens retaining frame to be released from the sub-guide shaft member at the retracting point.