PURPOSE: To prevent the exfoliation by fixing the upper end, intermediate end, and the lower end fixed parts, on a substrate at the side part of a tunnel inner decoration member consisting of the tiles fixed by an adhesive, on the surface of the substrate having each recessed side part on the upper side and lower side on a long hollow body.

CONSTITUTION: An anchor bolt A installed at a specific position on the surface of a substrate 1 is allowed to pass through a fixed hole on the lowest end member 13 in a lower end fixed part 9 and the fixed hole on a connecting member 10 for an intermediate fixed part 8 and an upper end fixed part 7, and the inner decoration members 2 are tightened by a double nut at the position for causing the vertical relation in the smooth angle, and between the guide piece of the lowest end member 13 and the fixed piece, the top on the back surface side of the side part of the lower part of the inner decoration member 2 is fitted. Then, the upper part of the inner decoration member 2 with which the lower part is fitted is attached on the guide piece of the connecting member, and each position of the upper side pressing 11 and the lower side pressing 12 is adjusted, and the bolt is allowed to pass through the connection hole, and fixed by a nut. The lower part of the inner decoration member 2 is fitted with the fixed piece of the lower side pressing 12, and the intermediate fixed part 8 is formed, and the inner decoration member 2 at the uppermost stage is fixed at the upper end fixed part 7.