A wavelength conversion structure includes a light guide formed of a light-transmissive member having a laser light incident port that allows the laser light to be introduced and a phosphor-containing layer that covers at least part of the surface of the light guide. The light guide has a light diffusing structure having asperities and a light reflecting film. The asperities are formed over the surface of the light guide except a laser light incident surface having the laser light incident port. The light reflecting film is formed over the surface of the light guide along the asperities except the laser light incident port and the portion covered with the phosphor-containing layer.