An automatic screw driver and a method for controlling the same, characterized by a fluid chamber (56) in which a suction force is developed so as to retain stably a screw (S) at a predetermined position irrespective of kind of material for the screw preparatory to a screwing operation of the driver, and a control circuit including a plurality of timers (T64,T66,T68,T70,T72) in order to perform a sequential operation consisting of steps of supplying the screw at the tip end of a bit (14), retaining perpendicularly the screw there and entering a standby state for the screwing operation, and actuating a driver when the sequential operation is completed, so that the screwing operation is facilitated and stabilized, resulting in a considerable improvement in the efficiency thereof.