PURPOSE: To certainly cut a female screw onto the cylindrical part of a T- shaped nut having direction characteristic by suppressing the revolution of a work by engaging the work at the top edge and inserting the top edge of a work pressing member which can be shifted in the parallel direction to a work cylinder part, into a base member.

CONSTITUTION: A work 51 is engaged with the engaging bar 23c of a work pressing member 21 by the cylindrical part 53, and the insertion amount of the pressing member 21 into a base member 31 is restricted by the stoppers 25a and 25b of the engaging member 23, and the member 31 is transferred as the member 21 shifts. The passage 32 of the member 31 into which the member 21 is inserted has an octagonal section, and as for the work 51 which is engaged with the member 21 and inserted into the passage 32, the revolution having a cylindrical part 53 as center is prevented. The rear edge part 45 of a tap 42 is bent into J- form, and exposed outside from the window 46 of a rotary cylinder 43. As the cylinder 43 is revolved, and a tap cutting edge 44 is shifted into the passage 32, a female screw is cut onto the work 51, which is springly discharged outside from the rear edge part 45.