A lens barrel for holding a lens group includes: a holding mechanism for
movably holding the lens group in a direction parallel to an optical
axis; an electromagnetic motor including a cylindrical stator with an
axis parallel to the optical axis being taken as a center axis and a
cylindrical rotor that is coaxial with the stator and rotates about the
center axis with respect to the stator; a converting mechanism for
converting a rotating motion of the rotor to a straight-ahead motion for
allowing the holding mechanism to move the lens group in the direction
parallel to the optical axis; and force applying means that applies a
magnetic force to the rotor in the direction parallel to the optical
axis.