Disclosed is a gasket, for a syringe, constructed so as to come into slidable contact with a syringe fluid-tightly within an external cylinder of the syringe. The gasket comprises a gasket body formed of an elastic body and a covering layer provided at least in a part, in the gasket body, which comes into contact with the syringe. The covering layer is formed of a composition containing a silicone resin and free from solid fine particles. The silicone resin comprises a condensate of a terminal silanol group-containing reactive silicone and has a siloxane bond derived from the silanol group.
