PURPOSE: To prevent a connecting screw from coming off during the screw tightening work by making an outlet of a magazine follow a nose part in a screw tightening device.

CONSTITUTION: A screw tightening device is provided with a screw tightening device body provided with a grip part 1, a nose part 3 which is provided in the screwing direction to the screw tightening device body 2 in a relatively slidable manner, and a magazine 5 to feed a connecting screw 4 to the nose part 3, a part of this magazine 5 is connected to the nose part 3, and another part is slidably connected to the grip part 1 to support the magazine 5 in a movable manner following the slide of the nose part 3.