Disclosed is an electro-optic modulator. The electro-optic modulator includes a lower clad layer disposed on a substrate, an optical waveguide disposed on the lower clad layer, traveling-wave electrodes respectively disposed on both sides of the optical waveguide and each having a first distance to the optical waveguide, and ferroelectric blocks disposed between the traveling-wave electrodes and the lower clad layer and each having a second distance to the optical waveguide, which is less than the first distance