PURPOSE: To produce a helical foamed item, by cutting a part of a thermoplastic foamed sheet, the orientations of the surface and undersurface of which are different from each other, into sheets rectangular in shape, and heating the sheets to be softened.

CONSTITUTION: Foamed sheet 1 is extruded in a direction shown by an arrow (a). At this time, an outer mold 21 is rotated in a direction shown by an arrow (d) while an inner mold 22 is rotated in a direction shown by an arrow (e). Thus the foamed sheet cylindrical in shape is obtained, the directions of orientations of the outer surface and the inner surface thereof being differed from each other. The cylindrical sheet is cut open along the length to obtain flat sheet. Rectangular pieces 5, 6 are cut out from the flat sheet. The pieces 5, 6 are heated to cause twisting so that helically bent foamed items can be obtained.