Jig and method for detecting misassembly of gasket

A method for detecting misassembly of a gasket, the method comprising:

• a first step of attaching, to a sealing surface of a jig, one end surface in an axial direction of a gasket assembled to a housing of a terminal block;
• a second step of accommodating, into groove portions provided in the sealing surface, at least a part of a lip portion of the gasket projecting along the axial direction from the one end surface as the sealing surface and the one end surface are brought into close contact with each other;
• and
• a third step of detecting leakage of an air flow by sending the air flow between the sealing surface and the one end surface from an air leak tester, and detecting misassembly of the gasket based on whether or not the air flow leaks.