To easily remove a door knob from an opening/closing member, to prevent pollution on a fitted face and to facilitate the opening/closing of the opening/closing member by arranging a suction cup body and a knob member provided at the center section on the opposite side to the sucking face of the cup body.

A suction cup body 5 has a pull member 4 protruded on the opposite side to a sucking face at the center section, and a flange section 10 locked on a curved plate 6 is integrally formed on the outer peripheral edge section of the cup body 5. The curved plate 6 has the insertion hole 11 of a screw shaft 8 at the center and is formed into a recessed curved shape. A fitting boss section idly rotatably coupled with a hanging member 13 and a handle section 15 connected to it are integrally provided. The handle section 15 of a fastening member 7 is rotated in the fastening direction, a screw shaft 8 is screwed to a screw tube, and the center section of the cup body 5 is pulled to the curved plate 6 side. A door knob 1 is posteriorly fitted easily to an opening/closing member by merely sucking the suction cup body 5 to the fitted face, and the opening/closing member can be easily opened or closed by the simple fitting work.