We developed a Fabry-Perot (FP) optical modulator with electro-optic (EO) films fabricated by aerosol deposition (AD). We found the ferroelectric Pb(Zr,Ti)O<sub>3</sub> film by AD produced a fairly high EO coefficient (>150 pm/V), approximately 10 times larger than that of LiNbO<sub>3</sub>. Since thick EO films greater than 5 μm can be deposited on a transparent electrode layer or a metallic mirror layer of the FP optical modulator by AD, the FP optical modulator can achieve low capacitance, resulting in high modulation speed. Transmittance spectra of the FP optical modulator coincided with the optical simulation spectra, which indicated that optical scattering in AD films and at the surface/boundary were very small. We demonstrated an optical intensity modulation with applied electric field to EO film of ferroelectric Pb (Zr, Ti)O<sub>3</sub>. We obtained a 4-dB modulation with 50 V for the 10-μm-thick modulator with dielectric multilayer mirror on a glass substrate.