An ion conductor includes: an inorganic porous film which includes multiple fine pores of which surfaces are bonded to multiple proton-donor functional groups; and an electrolyte material which is held in the fine pores of the inorganic porous film, and includes a cation component and an anion component. Further, a method of producing the ion conductor includes: mixing and agitating an inorganic sol, polymer particles, and a solvent; filtering a mixed liquid including the inorganic sol, the polymer particles, and the solvent to fabricate a membrane including the inorganic sol and the polymer particles; removing an extra solvent contained in the membrane formed by filtering, followed by drying the membrane; firing the dried membrane and removing the polymer particles to form an inorganic porous film; chemically modifying to introduce proton-donor functional groups onto surfaces of fine pores of the inorganic porous film; and impregnating the fine pores of the inorganic porous film introduced the proton-donor functional groups with an electrolyte material, followed by drying the inorganic porous film.