Powerful light-emitting diode device comprises at least one light-emitting diode light source mounted on a mounting plate made of a thermally conductive material, two-phase heat transfer elements arranged on both sides of the light-emitting diode light source and connected in thermal contact with one end to the mounting plate with the light-emitting diode light source, and connected to a group of side heat exchangers with the other end, and a support base with a support element including a flat part covering parts of the two-phase heat transfer elements. The two-phase heat transfer elements are made in the form of straight gravity heat pipes. The side heat exchangers and the support element are made in the form of segments of a serial radiator profile with straight vertical fins on one side and grooves for straight gravity heat pipes on the other, flat side of the base. The lower and upper edges of the side groups of radiator profiles, grooves for straight gravity heat pipes and straight gravity heat pipes are located at an angle to the horizon with the condensation zone of straight gravity heat pipes exceeding the evaporation zone. The condensation zones of the direct gravity heat pipes are located and mechanically fixed to ensure thermal contact in the grooves of the counter-oriented flat parts of each two serial radiator profiles of each group of side heat exchangers with straight vertical fins