The present invention provides a gasket for syringes which can be stored for a long time without any chemical liquid leakage. The present invention relates to a gasket for syringes, including a film laminated to a surface of the gasket, the film having a liquid-contacting portion and a sliding portion, the liquid-contacting portion being thicker than the sliding portion. Preferably, the liquid-contacting portion has a thickness at least 1.2 times the thickness of the sliding portion.