A method for producing a foamed blow-molded article, which includes extruding a physical blowing agent-containing foamable molten resin downwardly through a annular die to form a tubular foamed parison, clamping the foamed parison between split molds, and then blow molding it. At the latest before completion of the clamping of the foamed parison between the split molds, a gas is blown toward an inner peripheral surface of an upper portion of the foamed parison, the bottom portion of which has been closed, from a gas ejection outlet located within the foamed parison at a position immediately below the annular die to widen the foamed parison.