To provide a foam stabilizer for polyurethane foams which extremely reduces the amount of aldehydes generated with time even when incorporated into a polyurethane foam and a method for producing a polyurethanr foam by using this foam stabilizer.

The foam stabilizer for polyurethane foams comprises a polyether-modified silicone compound synthesized by the hydrosilylation reaction between at least an organohydrogenpolysiloxane and an allyl group-containing polyoxyalkylene compound, and the polyether-modified silicone compound has an amount of aldehydes generated on heat aging at 50°C for 0.5 hour in 0.23 N hydrochloric acid of not more than 100 ppm based on the mass of the polyether-modified silicone compound. The method for producing a polyurethane foam comprises foaming a mixture containing a polyol, an isocyanate compound, a blowing agent, a catalyst, and the above foam stabilizer.