A lens barrel includes a barrel main body, a first lens movement frame, a magnetic scale, and a magnetic sensor. The first lens movement frame is arranged movably in the optical axis direction of the optical system with respect to the barrel main body. The magnetic scale is provided to the first lens movement frame. The magnetic sensor is arranged on the outside of the barrel main body, and detects the position of the first lens movement frame with respect to the barrel main body by detecting the position of the magnetic scale with respect to the barrel main body.