To improve completeness of close fitting to the plus- or minus-shaped hole of a screw, and wear resistance by thermal-spraying particulate metal over a portion fitted to the hole of the screw or the like at the front end of a screwdriver bit so as to form a plurality of micro-protrusions at its surface.

At a blade part 4, particulate metal is thermal-sprayed between its front end and a blade shoulder part 4A to form a plurality of micro- protrusions 6 at the surface, which become a rough surface (approx. 50 to 70 grains/mm2). The micro-protrusions 6 have various sizes and shapes. When they are fitted to the plus-shaped hole of the screw or the like, the protrusions 6 come into close contact so as to bite the inside surface of the plus-shaped hole. Therefore, when the front end of the bit is fitted in the plus-shaped hole of the screw or the like, the screw or the like sits close to it, thus providing easy tightening work. The presence of the micro-protrusions 6 of the bit blade part 4 increases the come-out torque of a screwdriver bit 1, thus it is possible to prevent generation of come-out.