Abstract: A device for dispersing fine particles in the agglomerated state comprises a body, a fine particle channel provided in the body and terminating in a spout in the form of a slit, and a clearance provided in the body, inclined downstream with respect to the fine particle channel and communicating with the fine particle channel for emitting a gas into the fine particle channel. Since the spout is in the form of a slit, a large amount can be simultaneously dispersed without losing the dispersing performance of the single hole type dispersing device. When a plurality of such dispersing devices are attached to the combustion gas passage forming wall of a furnace and arranged so that the more upstream they are disposed, the greater is the throw of the reactant-containing gas emitted therefrom, the reactant is diffused in the combustion gas and uniformly distributed.