Abstract: An expansion molding apparatus for forming molded articles having consistently or partially thin-walls by expanding expandable thermoplastic resin beads in a cavity formed between molds with the application of heat. The apparatus has a moving device, for example, a cylinder which moles the molds in one orthogonal direction relative to a closing direction of the molds when filling the cavity with the expandable thermoplastic resin beads. After filling the resin beads in the cavity by moving at least one of the molds in at least one direction orthogonal to the closing direction so that a distance in a circumference section of the cavity becomes greater, the mold is moved back to the original position and the application of heat is performed to obtain molded articles.

Abstract: A method of forming molded articles having consistently or partially thin-walls by expanding expandable thermoplastic resin beads in a cavity formed between molds with the application of heat. The introduction of the resin beads is carried out after causing the width of a circumference section of the cavity to be greater than the diameter of the beads by moving one of or both of the molds in at least one direction orthogonal to a direction of closing the molds, the molds are then moved back to the normal positions, and the introduced resin beads are heated to form the molded article. Also, an expansion molding apparatus having a moving device such as a cylinder which moves the molds in at least one direction orthogonal to the closing direction during the introduction of the expandable thermoplastic resin beads, whereby consistently or partially thin-walled molded articles are manufactured.