To provide a thermal insulating wall panel capable of having not only sufficient plane efficiency without performing so severe quality control of materials, etc., but also maintaining the plane efficiency for a long period of time.

A thermal insulating wall panel 10 is stored between sill, girder and pipe column forming a wall of a building to promote thermal insulation after the completion of the wall. In that case, the thermal insulating wall panel 10 is brought into contact with the outsides of the sill, girder and pipe column, and it is constituted of a face material 11 closing openings among them, both up and down frame materials 12 fixed to the inside face of the face material 11 and arranged to both up and down sides of the sill and girder, a stud 13 holding thermal insulating materials such as urethane resin layer, etc., between both up and down frame materials 12 to fix, a plurality of reinforced battens 14 integrated in parallel with the frame materials 12 at specific intervals on the opposite side to the face material 11 of the stud 13 and a thermal insulating material 15 with which the reinforced battens 14, face material 11 and a space formed between both up and down frame materials 12 are filled.