PURPOSE: To reduce the permeation and infiltration leakage of an internal fluid flowing inside a gasket, improve airtightness, bending strength and handling performance, and facilitate punching so as to make manufacture easy by forming both surface layers of the gasket of expansion graphite sheets, and providing two layers or more of metallic foil or polymeric films.

CONSTITUTION: In an expansion graphite sheet gasket 10, both upper and lower surface layers of the gasket are formed of expansion graphite sheets 1A, 1C, and impermeable layers 2A, 2B formed of two layers of metallic foil or polymeric films are placed between the expansion graphite sheets 1A, 1B. The thickness of metallic foil is to be 0.01-0.25mm, and the thickness of the polymeric film is to be 0.005-0.05mm. Such an expansion graphite sheet gasket 10 is remarkably small in the quantity of permeation leakage and excellent in bending strength and handling performance. Also, since the total thickness of the metallic foil or polymeric films in use can be made small, the gasket can be easily punched into a specified shape so as to enable the manufacture of a ring gasket or the like.