To provide a heat insulating wall structure which has a prescribed adiabatic effect, can reduce component members and labor necessary for construction by reducing the component members.

This heat insulating wall structure includes: a skeleton 1 which defines indoor and outdoor sides of a building; waterproof paper 2 which is spread on the outdoor side surface of the skeleton 1; a lath 3 which is connected to the skeleton 1 while adjoining an outdoor side surface of the waterproof paper 2; and an inorganic lightweight molded article 4 which is connected to an outdoor side surface of the lath 3. In the heat insulating wall structure, the inorganic lightweight molded article 4 is molded by adding water to an inorganic hydraulic composition containing an inorganic hydraulic material and a fibrous material, and spraying a mixture of them on the lath 3.