PURPOSE: To resist a comparatively large thrust, quicken cut of a soft member, and make discharge of chips smooth.

CONSTITUTION: The top end angle α of a drill part 12 is set to nearly 120°, a blade 20 with cutting edge 23 formed on its top end is provided along a discharging groove 13 formed on the drill part 12 and a non-screw part 11, and the blade 20 consists of a thin wall part 25 in which a gradient is formed toward a screw part 10 so as to reduce the clearance to an axial core and a thick wall part 22 having the cutting edge 23. It is thus possible to screw-in a self drilling screw completely without breaking its drill part during its screwing at a large thrust. And also it is possible to achieve the drilling work on a metal member in a short time and prevent generation of any friction heat and burning and smoke of a soft member. And also it is possible to eliminate such an event that adhesive agent for plywood, etc., melts so as to stick on the blade, and discharge of chips is disturbed so that stable screwing work may be achieved.