A lens barrel includes a plurality of lens groups including first and second lens groups positioned closer to an imaging plane than the first lens group, a plurality of lens group frames including first and second lens group frames holding the first and second lens groups, respectively, a rotary cylinder to engage with the first lens group frame via a cam groove, surround the first lens group frame and be rotated around an optical axis to move the first lens group in the optical axis direction, a rotation transmission system to transmit a rotary force of the rotary cylinder, and a second frame driver provided inside of the first lens group frame and engaging with the second lens group frame via a cam groove to move the second lens group in the optical axis direction by the rotary force of the rotary cylinder transmitted via the rotation transmission system.