As a pretreatment of a manufacturing process of sintered ore, a sintering
material including iron ore, a SiO.sub.2-containing material, a limestone
base powdery material and a solid fuel type powdery material is projected
as a additional coating auxiliary raw material into the drum mixer with a
additional coating conveyor disposed in proximity to an exhaust outlet of
the drum mixer. Preferably, a sintering material excepting a limestone
base powdery material and a solid fuel type powdery material is charged
from a charge inlet of the drum mixer to granulate and in a region
disposed on a downstream side, an additional coating auxiliary raw
material including a limestone base powdery material and a solid fuel
type powdery material is added, and thereby until reaching the exhaust
outlet, the additional coating auxiliary raw material is deposited and
formed on a exterior coating portion of the sintering material.