The invention relates to the technical field of gear machining, in particular to a gear machining cooling device. The gear machining cooling device comprises a first conveying belt and an oil cooling box. A guide barrel is arranged above the end, located in the oil cooling box, of the first conveying belt, and the distance between the guide barrel and the first conveying belt ranges from 20 mm to 30 mm. A control rod with the upper end located in the guide barrel is vertically arranged in the oil cooling box, and the lower end of the control rod penetrates the bottom of the oil cooling box to be in sliding connection with the oil cooling box. A reset spring fixedly connected with the control rod is arranged on the control rod, and the other end of the reset spring is fixedly connected with the oil cooling box. The control rod comprises an upper conductive area and a lower insulation area, the conductive area is electrically connected with a power source of the first conveying belt, a metal wafer is in sliding connection with the control rod, and the metal wafer is electrically connected with the first conveying belt. Waste of electric energy can be reduced, the interval of adjacent gears on the conveying belt can be kept consistent all the time, and therefore the machining interval time of the next procedure can be conveniently controlled.