To facilitate the loading and treatment of a form separator cut-off member by holding an adhesive member having a hole section inserting a form separator thereinto with a basic body, and covering a concrete contact surface of the adhesive member with a water-soluble sheet.

A form separator cut-off member 1 is constituted of a ring-shaped basic body 2 boring a hole section 2a in the center and a ring-shaped adhesive member 3 stuck on the whole surface of the basic body 2 and boring a hole section 3a to stick a soft water soluble sheet thereon. The cut-off member 1 is inserted into the form separator from the basic body side, it is stopped at a middle part and is slantly inclined; and when the adhesive member 3 is turned several times so as to adhere to the form separator, the adhesive member 3 is wound around the form separator as a unit, and an interlocking part of the hole section 3a with the form separator is cut off. Then, when concrete is placed in the form, the water soluble sheet 4 is melted in alkali aqueous solution contained in the concrete, the adhesive member 3 is brought into contact with the concrete to form together as a unit, and the cut-off effect can be displayed. Work efficiency is promoted because a form stripping paper is not required, and since the cut-off member is not adhered to the adhesive members or another substance, excellent handling efficiency can be also obtained.