To facilitate transport and attachment of a form for a through hole to be formed on a skeleton such as foundation underground beams and an underground water tank partition wall by combining a plurality of unit members and forming the form.

Unit members 11 forming a frame for a through hole are made of foam resin, made into a shape divided in the circumferential and longitudinal directions of the through hole, a fitting projection part 12a is formed on one side of a circumferential side face 12, and a fitting recess part 12b on the other side thereof. In addition, a fitting projection part 13a is formed on one side of a longitudinal side face 13, and a fitting recess part 13b on the other side thereof. At the time of assembling of the frames, a frame for an assembling guide is formed, the unit members 11 are assembled substantially, and the projection parts and the recess part of the circumferentially and longitudinally adjacent unit members 11 are fitted and jointed. And a tightening band is tightened from the circumferential face of the unit members, proper reinforcing material is disposed in the inside if necessary, and the assembling of the form is completed. Accordingly, the unit members are easy to transport and joint, and the frame for through hole can be easily assembled.