Provided is an optical waveguide device including: a core having a stacked structure of at least three layers in which first thin films having a finite width and thickness and formed of a material having a relatively high electric conductivity and a second thin film having the same width as the first thin films and formed of a material having a lower conductivity than the material forming the first thin films are stacked in sequence, the first thin films being disposed in a first layer and an uppermost layer and adjacent to each other for interaction of surface plasmons; and a clad disposed around the core and formed of a material having a lower conductivity than the material forming the first thin films and a higher refractive index than the material forming the second thin film. The thin metal films of at least two layers having a high electric conductivity in the optical waveguide device can generate a combined surface plasmon mode and propagate the generated surface plasmon mode in the length direction of the thin metal films. Thus, a propagated signal suffers from a smaller propagation loss than a surface plasmon mode supported by a single thin film.