An optical device includes: a complex photonic crystal in which a plurality of materials with different refractive indices are placed periodically, whereby a plurality of photonic crystals 6c 1 to 6C n with a periodic refractive index distribution are arranged in a column in a direction of a common primitive lattice vector; ingoing optical waveguides 1c and 2c 1 to 2c n for allowing light to be incident upon the complex photonic crystal; and an outgoing optical waveguide 3c for receiving light output from the complex photonic crystal.