An optical wavelength conversion element includes: a wavelength conversion waveguide that has a periodic polarization reversal structure having alternately and cyclically formed domains of which polarization directions are inverted, that guides light as a fundamental wave corresponding to the periodic polarization reversal structure, and performs a wavelength conversion of the guided fundamental wave; a first clad that is made of a dielectric having a refractive index lower than that of the wavelength conversion waveguide and is provided in contact with the domains; a second clad that is made of a dielectric having a refractive index lower than that of the wavelength conversion waveguide and is provided in contact with the domains such that the second clad is opposed to the first clad film; a first conducting unit that electrically connects the domains in parallel via the first clad; and a second conducting unit that electrically connects the domains in parallel via the second clad.