The building module and method for erecting walls is composed of the supporting construction provided with the carrying ribs (1), placed at the settled distance one from another, to the above supporting construction at the lateral side of it one or two mantles (2) profiled on the outside surface and composed of at least one profile (3) placed simultaneously lengthwise and crosswise the carrying ribs are fixed. On the opposite side of the mantle, the flat mantle (2a) is fixed to the supporting construction, if necessary. On the top and at the bottom of the mantles there are preferably joint ends (8 and 8a) acting jointly which serve to join the adjacent modules whereas at the corners of buildings erected with their application they are provided with overlapping cruciform recesses (9 and 9a) made on the top and at the bottom of them. The carrying ribs have the uniform or segmented construction composed of cubes (1a) and attachments (1b) which are combined in a rigid way with the mantle profiles. In order to fix stable vertical supporting construction, the ports (14) earmarked for introducing threaded fasteners provided with the bolt have been made in the carrying posts (1).