PURPOSE: To reduce time number of parts by guiding a part to be guided which is provided in a nut part by means of a guide shaft by which a moving member is guided.

CONSTITUTION: By slidably inserting the guide shaft 23 through a guide hole 19a formed on the moving member 16 and a guide hole 28a formed in the nut part 25, the moving member 16 and the nut part 25 are slidably supported on the guide shaft 23. When a driving motor is driven, a feed screw 26 is rotated and the nut part 25 where the tooth of a tooth part 32 is engaged in the guide hole 28a is guided and moved by means of the guide shaft 23. Furthermore, the contact surface 22 of an engaging hole 21 formed on the moving member 16 is pressed by the contact part 36 of an engaging projection 35 protrusively provided at the upper edge of the nut part 25 with the movement of the nut part 25, the guide hole 19a of the moving member 16 is guided by the guide shaft 23, and the guide groove of a guide arm is guided by the guide shaft, so that a movable lens holder is moved in an optical axis direction.