A thermoplastic resin film excellent in slipperiness, wear resistance and transparency. The film contains 0.005 to 20 wt. % of specified fine particles of composite oxide comprising silica and at least one inorganic oxide other than silica. The film is preferably a polyester film having a hazing value of 5 % or less. It is suitable for use as magnetic tape, capacitor, photographic film and pressure-sensitive adhesive tape. The film is manufactured by adding a silicate of alkali metals, ammonium or organic bases and an alkali-soluble inorganic compound simultaneously to an alkali solution with pH 9 or above, generating fine particles of composite oxide without any control of the pH of this reaction solution, adding the obtaind sol to a thermoplastic resin and/or the reaction system thereof, and processing of a film.