Lens barrel capable of increasing shooting magnification while being miniaturized. A first lens group is caused to move in a direction of an optical axis by rotation of a second cam ring following rotation of a drive ring which has a focus cam groove on an inner periphery and is disposed on an outer periphery of a fixed cam ring having a cam groove and a rectilinear groove on an inner periphery. A second cam groove is disposed behind the first lens group in the direction of the optical axis. Rotation of the drive ring causes a follower of a focus group holding unit, which holds the second lens group, to follow the focus cam groove while being guided to move rectilinearly by the rectilinear groove. The follower following the focus cam groove causes the focus group holding unit to move in the direction of the optical axis.