Abstract: A screw tightening apparatus comprising a motor-driven tool, a screw magazine for screws affixed to a strip-like carrier, and a screw advancing and tightening means for advancing the screws one at a time to a preparatory screw tightening position in which a bit portion of the motor-driven tool may engage with the screw for tightening thereof. The screw advancing and tightening means comprises two axially movable portions, one of which is secured to the tool and the other one of which carries the screw magazine and a spring biased screw advancing mechanism. A push and pull member on the stationary portion is adapted to cooperate with a dog means on the spring biased screw advancing mechanism for advancement of a new screw at the end of the retractive movement of the movable parts into a rest position, subsequent to a completed driving home of a screw.