A lens barrel includes a lens group having an optical axis associated therewith, a fixed barrel and a rotatable barrel receives the fixed barrel. The fixed barrel has the lens group received therein and has a plurality of projections extending radially from the outer surface of the fixed barrel. The rotatable barrel rotatable relative to the fixed barrel about the optical axis has an inner latching groove and a number of insertion cutouts. The latching groove is defined in the inner surface of the rotatable barrel. The insertion cutouts are defined in a distal edge of the rotatable barrel with the inner latching groove and communicating with the latching groove. The insertion cutouts is insertable in the insertion cutouts and can engage in the latching groove for preventing the rotatable barrel to move axially relative to the fixed barrel.