A lens device includes: a lens barrel body having holes; guide bars supported by the lens barrel body and one ends of the guide bars are inserted in the holes; lens holding frames supported so as to be movable along the guide bars and are engaged with the guide bars; and pressing members that press the one ends of the guide bars in a direction perpendicular to the guide bars and are inserted in the holes. The pressing members have a falling-off prevention engagement protrusion engaged with the lens barrel body.