A gasket is provided, which is laminated with an inert resin film and has a reduced sliding resistance and a higher liquid sealability. The gasket (10) is used for a medical syringe (30), and includes a main body (11) made of an elastic material and an inert resin film (12) provided on a surface of the main body (11). The gasket (10) has a short cylindrical shape, and includes a plurality of annular ribs (13, 14, 15) provided on an outer circumferential surface (20) thereof and each having a sliding contact portion (16) to be kept in sliding contact with an inner peripheral surface of a syringe barrel. The plurality of annular ribs are axially arranged from a distal end to a rear end of the gasket (10). The sliding contact portion (16) of a distal annular rib (13) has a width that is 1 to 25% of a length of the outer circumferential surface (20) of the cylindrical gasket as measured axially of the gasket.
