A lens drive unit includes a movable member with lenses; and a guide portion configured to movably guide the movable member back and forth along a predetermined direction and rotatably guide the movable member about a predetermined rotational axis in a plane perpendicular to an optical axis of the lens. A distance r between the gravity center of the movable member and the rotational axis satisfies the following expression (A): r≦√{square root over (0.2J/M)}  (A).