Abstract: A screw driving and turning machine comprises: a body having a nose portion; a driving cylinder received in the body; a screw driving mechanism having a driving piston having a driving and turning bit slidably accommodated in the driving cylinder, wherein compressed air is fed into the driving cylinder to drive the driving piston, and a screw held in the nose portion of the body is driven to a state in which a head portion of the screw is raised; a screw turning mechanism having an air motor driven by a portion of compressed air fed to the driving cylinder, for turning the screw, which has been driven by the driving piston; a stop valve for opening and closing an air passage between the driving cylinder and the air motor, arranged in the middle of the air passage; and a contact arm slidably arranged along the nose portion, for operating the stop valve by being pushed to the body in accordance with pressing an end of the contact arm against a material into which the screw is driven, wherein the feed of compres