PURPOSE: To obtain a porous resin product which has a high multiplication factor of foaming, has little faulty molding of inclined thickness and has an improved stability of foam by a method wherein a reactive liquid material is cured and made to foam in a pressure reduced state.

CONSTITUTION: Material such as polyurethane foam and polyester foam, etc. is injected with a high pressure into a metallic mold 2 such as a steering wheel having an upper exhaust port 4 in a sealed case 1 by means of a high pressure foam making machine 3. At the point when a foam is started, the inside of the sealed case 1 is reduced in pressure up to 400mmHg preferably in 15sec by means of a vacuum pump 5 to make foam and to be cured. After preferably about 5min, the pressure within the sealed case is restored to an atmospheric pressure by opening an air inlet port 6 and the purposed cured porous resin product is obtained from the metallic mold 2.

EFFECT: Since the material can be filled into a mold in a stage of low viscosity, it can be used for a mold having a complicated type.