A lens drive unit includes: a driven member that moves a lens in an optical axis direction; a first gear rotated by a drive force of a drive motor; a second gear rotated by a drive force of a manual operation section; a third gear that engages with the first gear and the second gear and is rotated when the first gear is rotated but the second gear is not rotated whereas rotated when the second gear is rotated but the first gear is not rotated; and a fourth gear rotated when the third gear is rotated to transmit the drive force of the drive motor or the drive force of the manual operation section to the driven member, wherein the reduction ratio of the fourth gear to the first gear is set to be greater than the reduction ratio of the fourth gear to the second gear.