To provide a heat insulation waterproof structure of a structure and a heat insulation waterproofing construction method for the structure by use of a resin foaming material having excellent heat resistance.

This heat insulation waterproof structure 1 is provided with a heat insulation material 3 laminated on a substrate 2 of the structure, a fixing fitting 4 having a heat fusing material on a face exposed onto a surface side of the heat insulation material 3, fixed on the substrate 2 by anchoring, and fixing the heat insulating material 3 on the substrate 2, and a sheet 5 made of vinyl chloride resin laid on the heat insulation material 3 and stuck to the fixing fitting 4 by the heat fusing material. The heat insulation material 3 is formed by foaming a resin compound containing a copolymer A constituted of an aromatic vinyl unit, an unsaturated dicarboxylic acid anhydride unit, and an N-alkyl substitutional maleimide unit and a copolymer B constituted of an aromatic vinyl unit and a vinyl cyanide unit.