Abstract: Device for fastening at least one PV module (1) to a roof which comprises a trapezoidal metal sheet (2) with a trapezoidal bead (3) with two oblique sides (4, 5) and an upper side (6), wherein the device comprises: exactly one holding plate (10) for fastening to one of the two oblique sides (4, 5), a supporting face (11), a holding-down element (12) for clamping the at least one PV module (1) against the supporting face (11), a threaded shaft (13) which is assigned a central shaft axis (S) and which is provided for actuating the holding-down element (12) in the direction of the supporting face (11), exactly one hinge joint (R, 14, 15) which is assigned a central axis of rotation (R) and by means of which the exactly one holding plate (10) and the threaded shaft (13) are rotatably coupled to one another and which has a joint pin (14) and a pin receptacle (15), wherein the threaded shaft (13) and the joint pin (14) are arranged perpendicular to one another in such a way that a common plane (E) results in which