An organic-inorganic composite film comprising: an organic-inorganic composite including: an inorganic compound particle; and a polymer bonded to the inorganic compound particle, wherein a molecular weight distribution of the polymer is equal to or less than 2.3, wherein the inorganic compound particle and the polymer are bonded through a coupling agent which has a structure represented by the following formula: X-Si in the formula, X denotes a polymerization initiating group, R1 and R2 independently denote an alkyl group having 1 to 10 carbon atoms respectively, and R3 denotes an alkoxy group having 1 to 10 carbon atoms, a hydrogen atom, a hydroxyl group or a halogen atom; wherein the polymerization initiating group is an organic halide group represented by the following general formula or a halogenated sulfonyl group represented by general formula: in which R 1 and R 2 each independently denotes a hydrogen atom, an alkyl group having 1 to 20 carbon atoms that may have a substituent, an allyl group that may have a substituent, an aryl group having 6 to 20 carbon atoms that may have a substituent, an alkyl aryl group, or an alkyl aryl group that may have a substituent, and Z denotes a halogen atom; wherein the organic-inorganic composite further includes a free polymer not bonded to the inorganic compound particle, and a percentage of the free polymer is equal to or less than 20 mass% with reference to a total mass of the free polymer and the polymer bonded to the inorganic compound particle; wherein a percentage of voids in the film is 3 to 70 volume% with reference to a volume of the film; and wherein the organic-inorganic composite film has a refractive index of equal to or less than 1.36. an organic-inorganic composite including: an inorganic compound particle; and a polymer bonded to the inorganic compound particle, wherein a molecular weight distribution of the polymer is equal to or less than 2.3, wherein the inorganic compound particle and the polymer are bonded through a coupling agent which has a structure represented by the following formula: X-Si in the formula, X denotes a polymerization initiating group, R1 and R2 independently denote an alkyl group having 1 to 10 carbon atoms respectively, and R3 denotes an alkoxy group having 1 to 10 carbon atoms, a hydrogen atom, a hydroxyl group or a halogen atom; wherein the polymerization initiating group is an organic halide group represented by the following general formula or a halogenated sulfonyl group represented by general formula: in which R 1 and R 2 each independently denotes a hydrogen atom, an alkyl group having 1 to 20 carbon atoms that may have a substituent, an allyl group that may have a substituent, an aryl group having 6 to 20 carbon atoms that may have a substituent, an alkyl aryl group, or an alkyl aryl group that may have a substituent, and Z denotes a halogen atom; wherein the organic-inorganic composite further includes a free polymer not bonded to the inorganic compound particle, and a percentage of the free polymer is equal to or less than 20 mass% with reference to a total mass of the free polymer and the polymer bonded to the inorganic compound particle; wherein a percentage of voids in the film is 3 to 70 volume% with reference to a volume of the film; and wherein the organic-inorganic composite film has a refractive index of equal to or less than 1.36.