1. A gasket to be used for a medical syringe, the gasket comprising:a main body made of an elastic material; and
a film provided on a surface of the main body;
the gasket having a circumferential surface portion to be brought into contact with an inner peripheral surface of a syringe barrel of the syringe;
wherein said circumferential surface portion has a predetermined and fixed diameter along the gasket longitudinal direction, and has at least one projection provided thereon which projects circumferentially from a surface portion of the film, wherein said at least one projection has a height of not less than 15 ?m and not greater than 55 ?m and has a width of not less than 30 ?m and not greater than 75 ?m.