An object of the present invention is, in an optical modulator, to increase the production yield by enhancing the patterning accuracy of the electrodes, as well as to reduce the electrode loss by increasing the thickness of the electrodes. An optical modulator has a substrate 5 made of an electro-optical material; a modulation electrode 2A, 3A, 2B provided on the substrate 5; and an optical waveguide 1c provided on the substrate 5. Light propagating through the optical waveguide 1c is modulated by applying a modulation voltage to the modulation electrode. At least a part of the modulation electrode includes a base 2a, 3a formed on the substrate 5 and a projection part 2b, 3b having a width narrower than that of the base.