depending on the rotation of the worm wheel 24 due to the screw pair between the curved screw 14 and the femal screw thread 24a of the worm wheel 24 which is driven by the output power of the motor 13 the gear case 15 through the base 18 and the glass holder 16 moves in the opening direction or the closing direction together with the window glass 2 at this time the worm 26 of the gear case 15 and the motor 13 are connected by the flexible shaft 27 the motor 13 is movable rotatively in the plane parallel with the fame body 12 therefore the descending or the acsending movement of the gear case 15 relative to the curved screw 14 is not obstructed additionally while the case of using the power window apparatus according to this invention for opening and closing the window glass of the motor vehicle has been exemplified in this embodiment it is proper that the power window apparatus according to this invention can be used for opening and closing a window glass of a gymnasium a sunroom or the like for example furthermore the details of construction of the power window apparatus according to this invention is not restricted to the aforementioned embodiment as described above the power window apparatus according to this invention comprises a motor rotatable in the forward and the reverse directions a curved screw having curvature nearly equal to curvature of a curved window glass and fixed in parallel to the curvature of said curved window glass a movable unit connected to the motor and fitted onto the curved screw and.