To provide a technique that can produce a resin compositions, wherein inorganic fine particles can be used while avoiding blowing up of a powder and the inorganic fine particles are dispersed without resulting in reduction in productivity and increase in running cost.

The method for producing an inorganic fine particles aggregate, comprises the steps of: wet-grinding a raw mineral material, preferably inorganic fine particles from an inorganic waste, until they become inorganic fine particles with a mean particle diameter (d50) of 3 μm or less and a maximum particle diameter of 20 μm or less, to form slurry containing the inorganic fine particles; and drying the slurry by a spray drying process. The inorganic fine particles aggregate obtained by the production method has a good handling ability since the powder is hard to be blown up and they have a high flowability. The resin composition in which the inorganic fine particles are uniformly mixed can also be produced by using the inorganic fine particles aggregate since the aggregate is broken at a pressure when mixed with resin pellets.