To provide a flexible polyurethane foam having good vibration characteristics and suitable particularly for a seat for an automobile.A flexible polyurethane foam obtained by reacting a high molecular weight polyoxyalkylene polyol or a polymer-dispersed polyol containing fine polymer particles in the high molecular weight polyoxyalkylene polyol, with a polyisocyanate compound, in the presence of a catalyst, a blowing agent and a foam stabilizer, characterized in that an amino-modified silicone (F) having a silicon atom and a nitrogen atom in its molecule is used in an amount of from 0.00001 to 1 part by mass per 100 parts by mass of all active hydrogen compounds.