To facilitate construction of a heat insulating panel of a roof board surface or a floor surface consisting of a compound material of a heat insulating material and a rigid base plate and improve heat insulating efficiency.

A heat insulating material 2 is integrally laminated and adhered to a back surface of a base plate 1 having rigidity, and pin type support materials 3...3 head ends of which reach the back surface of the base plate l and rear ends of which come to be at the same level of a surface of the insulating material 2 are buried at positions corresponding to support crossbeams 5...5 on the side of the heat insulating material 2. Additionally, they are buried so that one side surface makes contact with the back surface of the base plate 1, the other side surface comes to be at the same level of the surface of the heat insulating material 2 and lengthy support materials continued in the cross direction of the base plate 1 arranged at a right angle relative to the support crossbeams 5...5.