To provide a screw member capable of preventing threads from being damaged even if excessively screwed.

This screw member comprises a bar member having a head part at an end and subsequently having a shaft part without threads and a bar member having a male screw part arranged in that order, a ring-shaped spring fitted onto the shaft part, and a female screw member engaged with the male screw part. The ring-shaped spring and the female screw member are positioned on the shaft part of the bar member allowing a joined member passed therethrough to fasten the joined member. The screw member further comprises a plurality of bearings, a feed bar rotatably supported on the bearings and having a threadless shaft part in a portion ranging from both sides of the male screw part at an intermediate position to the bearings between the bearings adjacent to each other, the ring-shaped spring fitted onto the shaft part, and the female screw member engaged with the male screw part. A fed body is connected to the female screw member and, according to the rotation of the feed bar, the female screw member is fed to a position on the shaft part while contracting the ring-shaped spring.