To provide cap mounting construction facilitating the work of a cap without taking manhour in execution and excellent in landscape efficiency and safety when the cap is mounted to pipe ends such as a post, a beam, etc., used for crossing prevention fence, protection fence, etc., constructed to a road, a bridge, etc.

The cap mounting construction is constituted of a pipe 1 with the edge section of the pipe drawn to the inside thereof and inclining the side wall of the edge section 12 to the inside and a cap 2 having a cover section 21 with a diameter larger than the inside diameter of an opening section thereof and forming a leg section 22 over the overall circumference in the rear side of the cover section 21. The leg section 22 is constituted of a groove section 221 with the outside diameter having the approximately same size as the inside diameter of the opening section 11 of the pipe 1 and an interlocking section 222 with a diameter slightly larger than the inside diameter of the opening section 11. Then, the leg section 22 of the cap 2 is inserted into the opening section 11 of the pipe 1, the end 13 of the opening section 11 of the pipe 1 is fitted to the groove section 221, the cap 2 is mounted to the pipe 1, and the cap 2 can be easily mounted only by bringing the cap 2 into contact with the end of the pipe 1 to push.