NOVELTY - The device for fixing a panel on a supporting structure, comprises two first elongated components (4) attached on the supporting structure and each provided with an adjustable clamping body of first two edges parallel to the panel, and two parallelly removable second elongated components (5) for connecting the first two components and each provided by an area for holding two second parallel edges of the panel. The second edges are perpendicular to the first edges held by the first profile components. The first elongated components are provided with a first connecting unit.    USE - The device is useful for fixing a panel on a supporting structure such as a roof of a building, where the panel is a frameless solar panel having a shape of rectangle, square or trapezoid.    ADVANTAGE - The device ensures rigid and precise fixation of an easily removable and reusable panel on a supporting structure of a building without any damage to the panel thus promoting moisture and condensation to the structure, absorbing any deformation or expansion of the structure and preventing leakage of water runoff in the structure.    DETAILED DESCRIPTION - The device for fixing a panel on a supporting structure, comprises two first elongated components (4) attached on the supporting structure and each provided with an adjustable clamping body of first two edges parallel to the panel, and two parallelly removable second elongated components (5) for connecting the first two components and each provided by an area for holding two second parallel edges of the panel. The second edges are perpendicular to the first edges held by the first profile components. The first elongated components are provided with a first connecting unit adapted for contacting with a second connecting unit located on the second elongated components. The first and second connecting units comprise connection members. The first connecting unit comprises parallel teeth formed on supports (11, 12) adapted to receive a part of a second elongated member. The second connection unit comprises parallel teeth formed on bearing areas divided in two parallel planes and having a shape complementary to the teeth of the first elongated components. The teeth of first and second elongated components extend along the directions, respectively, perpendicular or oblique to the longitudinal axis (AA') of the first elongated member and parallel to the longitudinal axis (XX') of the second elongated member on the entire length of elongated components. The clamping body of each first elongated component is used for holding two parallel edges of the two adjacent panels (1, 1'). Each second elongated component is provided with two holding areas distributed on two opposite sides of the second element and adapted to carry and holding two parallel edges of the two adjacent panels, and is reversible to use one or the other holding areas. The first and second elongated components are adapted to hold the edges of two neighboring panels in a same plane or two parallel planes, and provided with spouts for collecting and evacuating water received on the panels.    DESCRIPTION OF DRAWING(S) - The figure shows a partial perspective view of a device for connecting a panel on a supporting structure.    Panels (1, 1')    First elongated components (4)    Second elongated components (5)    Main body (9)    Lateral supports (11, 12)    Strap. (15)