Connecting device for firmly connecting two components (B1, B5) to one another, wherein the connecting device comprises: a first component which extends in a first planar extension with a plate-shaped first connection section which comprises a lateral end with an edge section surface which is oriented transversely to the thickness direction of the plate-shaped first connection section, wherein the edge section surface, when viewed in the first planar extension, is exclusively a side surface of a plate, wherein the first component comprises a fastening recess which is formed with the formation of a recess opening on the edge section surface of the first connection section extends therefrom in a recess extension direction transversely to the edge section surface of the first component and thereby forms recess longitudinal sections (31a, 32a) each with a thread receiving profile, wherein the recess longitudinal sections (31a, 32a) run along one another, wherein the thread receiving profile in each case comprises a sequence of receiving profile sections which extend transversely to the recess extension direction into the fastening recess, wherein the recess longitudinal sections (31a, 32a) run essentially parallel to one another, a second component with a plate-shaped second connection section, wherein the second component extends in a second planar extension which runs transversely to the first planar extension, wherein the plate-shaped second connection section comprises a through opening, a threaded screw with a screw shank, on the outer side of which a thread with a thread profile section received by the receiving profile sections is formed, wherein the threaded screw protrudes through the through opening from a second surface which is oriented contrary opposite to a first surface of the second plate-shaped connection section, wherein the receiving profile sections are each formed as two mutually extending thread flanks (81a, 81b), wherein the thread flanks (81a, 81b) are each formed as straight planes, the orientation of which runs along the recess extension direction, wherein an edge section which connects the thread flanks (81a, 81b) is formed as a straight plane or as a straight edge line section. a first component which extends in a first planar extension with a plate-shaped first connection section which comprises a lateral end with an edge section surface which is oriented transversely to the thickness direction of the plate-shaped first connection section, wherein the edge section surface, when viewed in the first planar extension, is exclusively a side surface of a plate, wherein the first component comprises a fastening recess which is formed with the formation of a recess opening on the edge section surface of the first connection section extends therefrom in a recess extension direction transversely to the edge section surface of the first component and thereby forms recess longitudinal sections (31a, 32a) each with a thread receiving profile, wherein the recess longitudinal sections (31a, 32a) run along one another, wherein the thread receiving profile in each case comprises a sequence of receiving profile sections which extend transversely to the recess extension direction into the fastening recess, wherein the recess longitudinal sections (31a, 32a) run essentially parallel to one another, a second component with a plate-shaped second connection section, wherein the second component extends in a second planar extension which runs transversely to the first planar extension, wherein the plate-shaped second connection section comprises a through opening, a threaded screw with a screw shank, on the outer side of which a thread with a thread profile section received by the receiving profile sections is formed, wherein the threaded screw protrudes through the through opening from a second surface which is oriented contrary opposite to a first surface of the second plate-shaped connection section, wherein the receiving profile sections are each formed as two mutually extending thread flanks (81a, 81b), wherein the thread flanks (81a, 81b) are each formed as straight planes, the orientation of which runs along the recess extension direction, wherein an edge section which connects the thread flanks (81a, 81b) is formed as a straight plane or as a straight edge line section.