PROBLEM TO BE SOLVED: To provide a gasket excellent in plugging, liquid-tightness, and slidability in the gasket laminated with an inert resin film used for a glass or resin-made syringe.SOLUTION: The invention relates to a gasket laminated by an inert resin film and having a plurality of annular ribs slidingly contacting with an inner wall of the syringe wherein a slide contact cross section of a tip annular rib is substantially straight having 10-55% of length of the straight part with respect to the whole length of the gasket, and is straightly enlarged in diameter in a rear end direction of the syringe in a range of 0.1-2.7% with respect to the minimum diameter of the straight part.
