Illumination device which comprises multiple illumination modules, each provided with a corresponding group of light sources. A liquid cooling plant is connected to the light sources in order to dissipate heat generated by the latter. The cooling plant is provided with a heat exchanger comprising a manifold provided with a passage channel having an inlet branch and an outlet branch. The heat exchanger further comprises a transmission block, which carries the illumination modules mounted thereon and is provided with multiple cooling tracks, which are hydraulically connected, parallel to each other, to the inlet branch and to the outlet branch of the passage channel of the manifold. Each cooling track is arranged at a respective illumination module in order to transfer the heat generated by the light sources of such illumination module to a coolant fluid which traverses the cooling track.