To provide a driver bit and screw capable of preventing conventional breakage of the screw by improving the constitution of a bit tip part fitted into a cross groove in a screw head and allowing the bit tip part to apply a vertical force to the screw in a combination between the driver bit and screw.

The cross groove 13 into which the driver bit tip is fitted is bored in the screw head 12, and the cross groove 13 is formed with a blade part fitting groove 14 formed by extending from the center of the screw head part 12 in the cross direction and penetrating therethrough to the edge, and a tip part fitting groove 15 provided in the center of the blade part fitting groove 14. The tip of the driver bit 1 is provided with a plane part 2 contacting parallel to the upper surface of the screw head part 12 so as to be vertically fitted into the cross groove bored in the screw head part 12, and four glade parts 3 extending from the center of the plane part 2 in the cross direction. The blade part 3 has the bottom surface formed slightly inclined from the edge towards the center and the plane central part comprising the combination of the plus driver bit and screw formed into an approximately conical tip part 4.