Patent ID: 8091592

Claim:
A substrate container comprising a container main body to contain a substrate and a check valve which has a cylindrical housing and a valve disc installed in the housing and controls gas flowing from and to the interior and the exterior of the container main body; and being formed by inserting the housing into a through-hole of the container main body, wherein, when an end of the valve located inside the container main body is defined as a front end: a check valve has a fixing ring that is mounted on a rear end side in a manner of being rotatable relative to the housing and fixes the housing to the container main body from rearward; the housing has a first housing installed on the front end side and a second housing inserted into the first housing at the front end and attached to the first housing; the first housing has a fixing piece protruding rearward from a rear end and a fixing claw being formed at a rear end of the fixing piece and fixing the fixing ring; the fixing ring has a cylindrical sidewall mounted outside the first housing and a flange protruding outward from the sidewall; and on an inner circumferential face of the sidewall, a guide recess extending in an axial direction and guiding the fixing claw, a detent protruding inward and abutting on the fixing piece, and a hook bent from the detent in a circumferential direction and locked to the fixing piece are installed, wherein the check valve further has a positioning mechanism to position the second housing to the first housing and a locking mechanism to lock the second housing to the first housing, and wherein the positioning mechanism has a positioning recess formed at a rear end of the first housing and a positioning protrusion being formed at the folded flange of the second housing and engaging with the positioning recess.