A sealing gasket for closure, made of a polyurethane elastomer obtained by reacting the following (A), (B) and (C): (A) a polyisocyanate component having an isocyanate group content of 5 to 38% by weight and average 2 to 3 functional groups, obtained by modifying an aliphatic isocyanate and/or an alicyclic isocyanate, (B) a polyol component having a hydroxyl value of 20 to 350 mgKOH/g and average 2 to 3 functional groups, and (C) a glycerin fatty acid ester having hydroxyl group(s);and a process for producing a closure using such a sealing gasket. The closure sealing gasket made of a polyurethane elastomer, obtained by the present invention, when used for a closure (e.g. a metal closure of a food container having good sealing properties), is little eluted, is less in swelling with an alcoholic beverage and less in the absorption of the odor of the alcoholic beverage into the closure sealing gasket, and is tough, and causes no yellowing.