A kneaded material obtained by heating and melt-kneading a toner composition and a water-based medium containing water are put into a container of a granulating apparatus, and heated by a heater while agitating, to disperse the kneaded material into the water-based medium in its softened state. A temperature at which a loss tangent value of the kneaded material reaches a predetermined loss tangent value A, specifically, 0.5 or more and less than 5.0, is inputted to a granulating temperature input section as a setting granulating temperature T1. The heater is then controlled by a control section so that a granulating temperature as a temperature of the water-based medium measured by a thermometer reaches the setting granulating temperature T1 inputted to the input section. Accordingly, the granulating temperature as a temperature of the water-based medium, and thus a temperature of the kneaded material in the water-based medium is adjusted to T1.