Provided is a method of producing an optical film which has an excellent strength and a low refractive index, and can be used for an optical antireflective film. The production method includes preparing a coating liquid including a capsule having a shell of a halogenated compound of an element of Group 2 by forming an emulsion of one of an aqueous solution including a compound containing an element of Group 2 and an aqueous solution including a compound containing a halogen, and an organic solvent, applying the coating liquid on a substrate, and heating the coating liquid, thereby forming an optical film containing a hollow particle having the shell of a halogenated compound of an element of Group 2.