Provided is a cylinder gasket which naturally has good sliding properties with respect to a cylinder, that does not require the application of silicon grease to a threaded hole into which a piston is screwed, that is not susceptible to the piston being dislodged, and which is not deformed even if subjected to heat sterilization. The cylinder gasket (10) comprises: a gasket main body (12) that is made from a thermoplastic elastomer and which has sliding surfaces and the tip surface covered with a friction-reducing film (20), and has a recess (16) formed on the surface on which a piston (P) is mounted and a base member (14) made from plastic having a higher softening point than the thermoplastic elastomer that forms the gasket main body (12), said base member having a threaded hole (18) into which the tip of the piston (P) is screwed, and said base member being mounted to the recess (16) with the threaded hole (18) open to the exterior.
