To provide a structure for installing a pressure sensor 6 on a head gasket 1 allowing easy installation regardless of installation space and a pressure in a cylinder 4 to be detected.

The pressure sensor 6 is buried in the component member of the head gasket 1 near the inner peripheral surface 5 of the head gasket 1 for receiving a combustion pressure occurring in the cylinder 4. In detail, the pressure sensor 6 is disposed through a vent passage opening at a position facing the inner peripheral surface 5 of the head gasket 1 receiving the combustion pressure. Only by the conventional process in which the head gasket 1 is installed by providing it between a cylinder block 2 and a cylinder head 3, the installation of the pressure sensor 6 is completed regardless of the installation space, and the pressure in the cylinder 4 can be detected.