The present invention relates to a cooling device for disc cutters, which can include: a curved, tubular guide (6), with a radius of curvature slightly greater than the cutter disc and concentric with the periphery of the disc (2); a curved cannula (4), made of semi-rigid material, mounted inside the curved guide capable of longitudinal movement between two end positions, connected to a tube (3) for supplying coolant to a nozzle (5); and means for attaching the cannula (4) in any position comprised between the two end positions of movement with respect to the curved guide. The nozzle (5) moves over a lower sector (21) of the periphery of the disc, and during the cutting of parts (P) of different thicknesses, said nozzle (5) is located at different heights and facing the disc (2) contact and penetration area in the part (P) to be cut.