The self-bearing prefabricated construction element for erecting external walls in buildings, composed of external and internal panels integrated with the insulating material which goes in between, characterized in that the external panel (1) forms the face of architectural concrete which serves as the facade finishing layer, and the internal panel (2) is preferably made of structural concrete, where the insulation (3) in between the panels and integrated therewith is made of a foam material of density ranging from 10 kg/m3 to 55 kg/m3 and features at least two slots (4) in the vertical side zones.