PURPOSE: To facilitate manufacture, and to prevent the waste of a material by placing a reticulate body on the top face of a first cavity, into which the liquefied foamed material is injected, positioning a second cavity, putting a gasket base body having upper and lower through holes and contact-bonding these first cavity, second cavity, reticulate body and gasket base body and foaming a resin in the manufacture of the title gasket.

CONSTITUTION: A liquefied foamed material 30 such as soft polyurethane foam is injected into the annular recessed section of a first cavity 26. A reticulate body 32 made of plastics is placed on the base of a second cavity 28. An annular gasket base body 34 consisting of an ABS resin, etc., and having vertical through-holes 3 is put on the reticulate body 32 while leaving a slight clearance 36 from the side face of the second cavity 28, and contact-bonded, and the first cavity 26 is closed by the gasket base body 34. A foaming resin is foamed. Consequently, a gasket 42 in which the reticulate body 32 and the gasket base body 34 are unified is obtained. Accordingly, the gasket can be manufactured easily without the waste of the material.