An optical waveguide element includes an optical waveguide arranged on a main surface of an optical substrate, and a control electrode configured to control light waves propagating through the optical waveguide. The control electrode includes a first control electrode and a second control electrode facing each other across the optical waveguide on the main surface of the optical substrate. The first control electrode and the second control electrode each include a common electrode extending along the optical waveguide, a plurality of segment electrodes arranged closer to the optical waveguide than the common electrode and divided along an extending direction of the optical waveguide, and a plurality of connection electrodes connecting each of the plurality of segment electrodes to the common electrode. A low dielectric layer having a relative dielectric constant lower than a relative dielectric constant of the optical substrate is arranged between the common electrode and the optical substrate.