PURPOSE: To provide a method of fairly effectively mass-producing a multi-type of ferrite product and its device when manufacturing soft ferrite by an atomizing roasting method.

CONSTITUTION: At least two kinds of raw material liquid and at least two stock tanks 41, 42 are prepared. The material liquid is mixed at a specific mixture ratio and the mixture liquid is atomized and roasted by an atomizing roasting furnace 2 to change roasted matter into a slurry to obtain a first base material slurry A, which is stored in a first stock tank 41. Simultaneously, mixture liquid having different mixture ratio is atomized and roasted to slurry roasted matter to obtain one type or more of a second base material slurry B, which is stored on a second stock tank corresponding to the slurry type. The mixture ratio of these base material slurries A, B to a base material C of other oxides other than roasted matter as occasion demands is changed and these are mixed to obtain a plurality of ferrite material slurries to obtain a plurality of types of soft ferrite having different compositions from these obtained materials.