Provided is a hollow foamed blow-molded article having a high heat resistance, employing a thermoplastic resin composition containing a mixed resin of a polyphenylene ether resin and a polystyrene resin, as a base resin. The foamed blow-molded article, may be produced by extruding a foamable molten resin composition obtained by kneading the thermoplastic resin composition and a blowing agent to form a foamed parison, and blow molding the foamed parison. A glass transition temperature of the thermoplastic resin composition is 110° C. or higher. A melt viscosity of the thermoplastic resin composition at a temperature of the glass transition temperature+80° C. and at a shear rate of 100/sec is 3000 to 9500 Pa·s. The physical blowing agent is a blowing agent containing a hydrocarbon compound having 3-5 carbon atoms. A blending amount of the physical blowing agent is 0.4 to 1 mol per kg of the thermoplastic resin composition.