A molding method for a resin molded article includes: a step of sandwiching a sheet-shaped resin in a molten state extruded downward by a pair of rollers, and sending out downward the sheet-shaped resin in the molten state by a rotational driving of the rollers so as to allow a first stretching; a step of drawing downward the sheet-shaped resin in the molten state sent out downward so as to allow a second stretching; a step of disposing the sheet-shaped resin in the molten state that is drawn in a side portion of a mold disposed below the pair of rollers; and a step of molding the sheet-shaped resin into a shape conforming to a mold shape by depressurizing a sealed space formed between the sheet-shaped resin in the molten state and the mold and/or pressurizing the sheet-shaped resin toward the mold.