Provided is a method of desulfurization of molten iron by means of a mechanical stirring type of desulfurization apparatus equipped with an impeller. The desulfurization treatment is conducted by blasting a CaO-based desulfurization agent having a particle size of 30-400 µm in diameter with a carrier gas through a top lance onto the surface of the impeller-stirred molten iron bath. Thereby, the desulfurization agent can be added at a high addition efficiency without causing aggregation of the added desulfurization agent. Thus the desulfurization can be conducted stably at a high efficiency.
