To simplify the structure of a lifting/lowering device for lifting/lowering a body to be lifted up and down by leading out and winding in the code.

The light shielding screen lifting/lowering device 1 comprises: a code 4 fixed to a light shielding screen 2; a winding drum 5 to which the code 4 is wound around; a bearing 53 fixed to a support frame 8 and arranged on the winding drum 5; a support shaft 6 supporting the right-side end of winding drum 5 threadedly engaged with a recessive screw hole 53a of bearing 53, and an external groove screw member 61; a supporting part 74 supporting a supported part 51 formed at the left edge of winding drum 5 freely sliding in axial direction of winding drum 5; a motor 71 with a supporting part 74 attached to the rotary shaft 71a; a rotation control part 52 to control the rotation of supporting part 74 for the winding drum 5; and a driving unit 7 for rotating the rotary shaft 71a of the motor 71.