To provide a fixed material of a pipe material for fixing the pipe material for boring a cave into a wall making use of a large number of bars like beams for a building structure to a fixed position.

The fixed material of the pipe material is constituted of two fixed sections of a pipe material inside fixed section 1 and a pipe material outside fixed section 2, the pipe material outside fixed section 2 is an approximately semi-circular fixed section, and the pipe material outside fixed section 2 is fixed to a form so as to turn it to the downward side for fixing it to the form. An approximately half pipe material fixed in the first place is fixed so as to hold between the pipe material inside fixed section and pipe material outside fixed section, and the following half pipe material is mounted so as to connect to the upper part of the pipe material fixed in the first place. The fixed material of the pipe material is fixed to the form with nails by means of nail holes for a form fixed section. When the fixed material of the pipe material is hard to fix to the fixed position because of having a large number of bars, it can be fixed to the form by making use of an arm attached form fixing arm section 5.