A thermoplastic resin composition, comprises a thermoplastic resin (A) and thermoplastic resin fine particles (C) carrying a colloidal inorganic substance (B), and contains the colloidal inorganic substance (B) in a proportion of 0.01-0.8 wt. % of the total of the thermoplastic resin (A), the colloidal inorganic substance (B) and the thermoplastic resin fine particles (C). The thermoplastic resin composition effectively prevents the plateout without impairing inherent properties of the base thermoplastic resin, by containing the colloidal inorganic substance (B) showing a plateout-prevention effect in a small amount and in a good dispersion state.