Patent ID: 7556171

Claim:
A tank, comprising: a valve, and a tank main body having a container-like shape into which said valve is inserted, said tank main body having: a circumferential wall which is configured by integrating an outer circumferential wall on the outside and a liner on the inside except for the area around a through-hole that is formed in the circumferential wall; and a cap made of a metal that is fitted into said through-hole in said circumferential wall, wherein, at said liner, an adjacent part is formed as an integral part thereof, said adjacent part constituting an inner end portion of said through-hole; in the inside of the adjacent part, a high-hardness part having a higher hardness than the liner is provided; an inner end portion of said cap forms a protruded part that protrudes inwardly towards an inner side of the tank, and in an axial direction of the tank, and contacts the adjacent part of said liner; and a seal member being provided at an outer circumferential surface of said protruded part of said cap and an inner circumferential surface of the adjacent part of said liner.