A panel for constructing a wall or a ceiling of a construction, - having an insulation core formed of a thermally insulating construction material and - having face sheets (3, 4) prefabricated from a sheet metal (S1, S2) at least partially covering the insulation core on its outer faces - wherein at one first narrow side of said panel (1, 2) two engaging protrusions (8, 9) filled with material of the insulation core are formed each supporting an engaging shaped element (19, 20), each of the engaging protrusions being alotted to one of the outer faces (10, 11) of said panel (1, 2) and being enclosed by the sheet metal of said face sheet (3, 4), which is related to the respective outer face (10, 11) of said panel (1, 2), and wherein a groove (21, 22) is formed into each narrow side of said panel (1, 2) opposing said first narrow side, wherein the groove is formed adjacent to each of the outer faces (12, 13) of said panel (1, 2), wherein the groove is laterally defined by an outer long side, which is related to the corresponding outer face (10, 11) of the panel (1, 2), an inner long side opposing the respective outer long side and a base connecting the outer long side and the inner long side, and is adapted to the shape and position of the engaging protrusions (8, 9) of said panel (1, 2) so that the engaging protrusions (8, 9) of said panel (1, 2) may each positively engage in a corresponding groove (21, 22) of a similarly shaped second panel positioned closely next to the first panel, characterized in that - the outer long side, the inner long side and the base of the grooves (21, 22) are covered by sheet metal of the face sheet (3, 4) related to the respective outer face (10, 11), - each engaging shaped element (19, 20), each of which is supported by the engaging protrusions (8, 9), is positioned on that side of the respective engaging protrusions (8, 9), which is related to the inner long side of groove (21, 22) corresponding to the respective engaging protrusion (8, 9), - each of the grooves (21, 22) is defined by a wall portion (23, 24) on its respective outer face, wherein the outer face of the wall portion is aligned to the respective outer face (12, 13) of the wall panels (1, 2), and the thickness of the wall portions (23, 24) of the panel (1, 2), which are covered with the sheet metal of the respective face sheet (3, 4), is slightly undersized with respect to distance, by which the engaging protrusions are offset with respect to the outer faces (12, 13) of panels (1, 2), and - at each of the inner long sides of the grooves (21, 22) an engaging shaped element (31, 32) is formed and positioned so that in an assembled state, the engaging protrusions (8, 9) of the second panel are flexibly and elastically engageable, via their respective engaging shaped element (19, 20), with the engaging shaped element (31, 32) at the inner long side of the respectively related groove (21, 22) of panel (1, 2), so that, in the assembled state, the engaging protrusions (8, 9) abut with an initial tension with their engaging shaped elements (31, 32) the inner long side of each related groove (21, 22). - having an insulation core formed of a thermally insulating construction material and - having face sheets (3, 4) prefabricated from a sheet metal (S1, S2) at least partially covering the insulation core on its outer faces - wherein at one first narrow side of said panel (1, 2) two engaging protrusions (8, 9) filled with material of the insulation core are formed each supporting an engaging shaped element (19, 20), each of the engaging protrusions being alotted to one of the outer faces (10, 11) of said panel (1, 2) and being enclosed by the sheet metal of said face sheet (3, 4), which is related to the respective outer face (10, 11) of said panel (1, 2), and - the outer long side, the inner long side and the base of the grooves (21, 22) are covered by sheet metal of the face sheet (3, 4) related to the respective outer face (10, 11), - each engaging shaped element (19, 20), each of which is supported by the engaging protrusions (8, 9), is positioned on that side of the respective engaging protrusions (8, 9), which is related to the inner long side of groove (21, 22) corresponding to the respective engaging protrusion (8, 9), - each of the grooves (21, 22) is defined by a wall portion (23, 24) on its respective outer face, wherein the outer face of the wall portion is aligned to the respective outer face (12, 13) of the wall panels (1, 2), and the thickness of the wall portions (23, 24) of the panel (1, 2), which are covered with the sheet metal of the respective face sheet (3, 4), is slightly undersized with respect to distance, by which the engaging protrusions are offset with respect to the outer faces (12, 13) of panels (1, 2), and - at each of the inner long sides of the grooves (21, 22) an engaging shaped element (31, 32) is formed and positioned so that in an assembled state, the engaging protrusions (8, 9) of the second panel are flexibly and elastically engageable, via their respective engaging shaped element (19, 20), with the engaging shaped element (31, 32) at the inner long side of the respectively related groove (21, 22) of panel (1, 2), so that, in the assembled state, the engaging protrusions (8, 9) abut with an initial tension with their engaging shaped elements (31, 32) the inner long side of each related groove (21, 22).