A check valve that can be used even under high temperature conditions is provided as a result of improving heat resistance and solving the problem of "the stopper sticking to the sealing member" that is associated with high temperature use. The opening of a fluid channel (2a) provided in a first body (2) is blocked by a stopper (5), which is compelled by a compelling member (7), coming into contact with a sealing member (4). The sealing member (4) is a post-cured perfluoro elastomer packing. A ring-shaped sealing part (6) that contacts the sealing member (4) in a line is formed on the stopper (5).