A lens barrel includes a distance adjustment ring for moving a movable lens group; a hand-operated ring and a motor for rotating the distance adjustment ring; a one-way rotational transfer mechanism which transfers torque of the hand-operated ring to the distance adjustment ring when the hand-operated ring is manually rotated, and prevents torque of the distance adjustment ring transferring to the hand-operated ring when the distance adjustment ring is rotated by the motor. A circumferentially-uneven-width-space forming portion formed on an annular overlapping portion of the hand-operated ring, is shaped so that a torque transfer member, installed in an accommodation space between the annular overlapping portion and-a torque transfer cylindrical surface on the distance adjustment ring, wedges between the circumferentially-uneven-width-space forming portion and the torque transfer cylindrical surface to transfer the torque of the manually rotated hand-operated ring to the distance adjustment ring.