PURPOSE: To prevent a separator from being exposed by partially inserting the end of the separator holding a permanent form into a through hole formed in the permanent form and screw-threadly engaging a fastener with the end.

CONSTITUTION: A threaded end portion 12A of a separator 12 is inserted to the point midway in a through hole 11 of a permanent form 10. Next, an internal thread portion 1 of a temporary fastener is screw-threadly engaged with the threaded end 12A and the fastener is tightened until a washer 3 makes contact with the outer surface of the form 10, following which a metal pipe 30 is brought into contact with the outer surface of the form 10 so that a bolt portion 21 of a form tie 21 is threadedly engaged with an external thread portion 2 of the fastener and if the forward end of the bolt portion 21 contacts a nut 4, a nut 22 is screwed onto the portion 21 to press the pipe 30. And after concrete 15 is placed inside the form 10, the form tie 20, bolt portion 21, and pipe 30 are removed. Further after the concrete 15 is completely cured, the fastener is removed.