Abstract: A vehicle-mounted emulsion dispersing device including a dispersing nozzle that is opened and closed by an opening/closing device, an emulsion tank that stores emulsion, and an emulsion pump for pumping emulsion from the tank to the nozzle and spraying the emulsion from the nozzle. A control device controls the emulsion pump and the dispersing nozzle so that the rate of emulsion dispersion coincides with a set value. A method of dispersing emulsion using the emulsion dispersing device wherein the control device intermittently disperses the emulsion by intermittently opening and closing the opening/closing device so that the area of dispersed emulsion is continuous from front to back.