PURPOSE: To provide adiabatic wall panel having uniform strength and adiabatic property without necessity of after-treatment in a method that a melt liquid material of adiabatic substance is poured into a frame whose upper side is opened and obliquely positioned, and is repositioned in a horizontal status after pouring the said liquid which will foam thereafter to complete wall panel with cured adiabatic layer.

CONSTITUTION: Wall panel blank 1 is first inclined by angle θ1, and melt of foaming insulation substance is poured on the inner bottom 1a of blank 1 from nozzle 4. When the melt dropped to a point 7 just under the nozzle 4 flows down to a point 8 which has nearly equal distance l2 from flange 3 to that l1of the point 7, the pouring from nozzle 4 is terminated and the blank 1 is reprositioned to horizontal status. As the melt is foaming, its upper surface is gradually pressed by press member 9 so as to stretch the foaming melt until it reaches at inner faces of both flanges 3 and to fill up whole inner bottom 1a uniformly. This process can prevent insulation substance from its scattering away, and contributes to make excellent adiabatic wall panel with uniform adiabatic feature and strength as a whole