PROBLEM TO BE SOLVED: To provide a pad for an electrode composed of a polyurethane hydrous gel, having a sufficient threshold strength, preferably excellent in elastic force, durable to continuous usage and having little strength deterioration over time, and having reasonable elongation rate.SOLUTION: A polyurethane hydrous gel (1) is prepared by gelating a composition for forming a gel containing a polyisocyanate component and a polyol component, and has a methylenediphenyl structure in the main chain, wherein the polyisocyanate component before the urethanization reaction contains preferably 20 to 50 wt.% of a polymeric MDI (Cr-MDI).
