A preparing method of an electrostatic charge image developing toner includes: aggregating binder resin particles in a dispersion containing the binder resin particles to form aggregated particles; and coalescing the aggregated particles by heating a dispersion containing the aggregated particles to form toner particles. The aggregating includes stirring the dispersion in the aggregating at a required stirring power of 1.0 kW/m3 or more and 6.0 kW/m3 or less per unit volume, and the preparing method satisfies the following Requirement (1), in which Requirement (1): a viscosity of the dispersion during the stirring is 5 Pa·s or more and 50 Pa·s or less at a shear rate of 1/s, where the viscosity of the dispersion is measured at a sample temperature of 25° C. using a part of the dispersion as a sample.