Rubber product, test jig and test device for sealing member, and leakage detection member

A test jig for performing a leakage test of a sealing member having a ring shape that seals a gap between two members, comprising

• a mounting table that has a mounting surface on which the sealing member is mounted,
• an upper disposed member that is disposed on the upper side of the sealing member mounted on the mounting table, and
• a leakage detection member that is positioned on the outer side of the sealing member mounted on the mounting table, wherein
• the leakage detection member includes a gas chromic material that changes a color thereof reversibly or changes an electric resistance value thereof, due to oxidation-reduction reaction, and
• when leakage from the sealing member occurs, a part of the leakage detection member where the leakage from the sealing member is observed changes a color thereof.