The present invention generally relates to a screw driver bit, and more particularly to the improvement of a drive bit of a screw driver bit for matching with a screw. A drive recess of the screw head includes four symmetrical arc-shaped grooves and a square groove formed at the center of the arc-shaped grooves. Also, the drive bit of the screw driver bit is used for matching with the screw, and correspondingly includes four symmetrical arc-shaped protrusions and a square protrusion formed at the center of the arc-shaped protrusions. Thus, the types of slot, cross, cross-square combination, square and double-cross of the drive bit of the conventional screw driver bit, and the screw driver bit of the present invention all can be adapted to insert into and engage with the drive recess. Particularly, when the screw driver bit having arc-shaped drive bit is simultaneously used, it is easy to control the screw during locking and to generate larger driving torque, thereby achieving the object of practical utility and economizing effort.