Flexible polyurethane foam

The present invention relates to flexible polyurethane foam. More specifically, the flexible polyurethane foam is methylene diphenyl diisocyanate (MDI) exhibiting an excellent comfort of low hardness and high elasticity and having a broken cell structure of an open cell pore shape having an apparent density of 25-31 kg/m^3, a compression hardness of 4.2-5.7 kgf/314 cm^2, a resistance elasticity of 60-70%, and an elasticity ratio of 0.05-0.10.