NOVELTY - Low refractive index film-forming composition prepared by: (A1) mixing a fluoroalkyl group-containing silicon alkoxide with a silicon alkoxide to obtain a mixture; (A2) mixing water, formic acid, and organic solvent comprising alcohol, glycol ether or glycol ether acetate with the mixture to produce a hydrolyzate of the mixture; and (A3) mixing silica sol obtained by dispersing beaded colloidal silica particles in a liquid medium with the hydrolyzate, is claimed.    USE - The composition is useful for forming a low refractive index film (claimed), which is useful in a display panel, a solar cell, an optical lens, a camera module, and a sensor module.    ADVANTAGE - The obtained film has low refractive index, high antireflection effect and superior wettability.    DETAILED DESCRIPTION - Low refractive index film-forming composition prepared by: (A1) mixing a fluoroalkyl group-containing silicon alkoxide with a silicon alkoxide at a mass ratio of 1:0.6-1:1.6 to obtain a mixture; (A2) mixing 0.5-5 parts by mass of water, 0.005-0.5 parts by mass of formic acid, and 1-5 parts by mass of organic solvent comprising alcohol, glycol ether or glycol ether acetate with 1 part by mass of the mixture to produce a hydrolyzate of the mixture; and (A3) mixing silica sol obtained by dispersing beaded colloidal silica particles in a liquid medium with the hydrolyzate such that a content of silicon dioxide in the silica sol is 50-500 parts by mass with respect to 100 parts by mass of content of silicon dioxide in the hydrolyzate, is claimed. The beaded colloidal silica particles are formed of spherical colloidal silica particles having an average particle size of 5-50 nm and a metal oxide-containing silica through which the spherical colloidal silica particles are linked to each other. A ratio (D1/D2) of an average particle size (D1) of the spherical colloidal silica particles, which is measured with a dynamic light scattering method, to an average particle size (D2) of the spherical colloidal silica particles, which is obtained according to an expression as given in the expression, is greater than or equal to 3 nm. The average particle size (D1) is 30-300 nm. The spherical colloidal silica particles are linked to one plane.