PURPOSE: To improve the surface strength, bending strength and compression strength of plastic foam by filling the lengthy article of foamed plastic in an extruder, and covering it with the plastic by using a die.

CONSTITUTION: The sheet of crosslinked polyethylene foam 2 (density of about 0.1g/cc, width of about 100mm and thickness of about 10mm) is passed through a cross head extruder, covered with soft vinyl chloride 1 of about 180°C of material temperature in thickness of about 0.5mm, and cut in length of about 3000mm. Then, the sheet is thermally press bonded at both ends with the vinyl chlorides of the same thickness. The obtained foamed composite sheet has excellent surface strength, bending strength and compression strength, does not absorb water even in water, has excellent weather resistance and is inflammable, and hence satisfactory as heat insulator, cushioning material or floating material.