PURPOSE: To promote heat insulation efficiency, lightweight efficiency, compression resistance and lending resistance by increasing percentages of hollow sections filled with insulating foam, and making an intermediate layer as a honeycomb construction.

CONSTITUTION: A proper number of veneers having alternately stripped unevenness sections on both sides are made to laminate and adhere to form an intermediate layer 3 of a panel so that the unevenness sections of the veneer are not fitted to each other. Flat plates are laminated on both sides of the intermediate layer 3, and hollow sections 5 formed of recess sections of the veneer of the intermediate layer 3 are filled with insulating foam to form an insulating panel 1.