PURPOSE: To obtain the foam, capable of maintaining the breaking strength and elongation under high-temperature conditions at high levels, reducing defectiveness in hot molding and improving the yield and useful as an interior automotive trim, etc., by dividing a foam and specifying the difference in gel fraction between a layer of the maximum gel fraction and a layer of the minimum gel fraction.

CONSTITUTION: This foam has 35-85% average gel fraction and the difference in gel fraction between a layer of the maximum gel fraction and a layer of the minimum gel fraction is ≥10% in trisecting the foam in the thickness direction. Furthermore, the foam is preferably obtained by blending a polyolefinic resin with an organic foaming agent, a cross-linking assistant, an antioxidant, etc., producing a sheet according to the extrusion sheeting, exposing the resultant sheet to radiation and cross-linking, etc., the sheet.