a method of producing a skin - covered foamed plastic article , which includes preparing a lower mold which has a cavity formed therein ; putting a bag - shaped outer skin member into the cavity , the skin member having a porous inner layer ; pouring a foamable material for the foamed plastic article into the bag - shaped outer skin member ; and controlling a pressure in the cavity in such a manner that the inner layer becomes saturated to a predetermined degree during curing of the material .