A photonic crystal device according to the present invention includes: a substrate 201; a periodic structure portion 206 formed in or on the substrate 201, the periodic structure portion 206 having a plurality of holes 2050 and 2051 arranged in a periodic array; at least one optical waveguide 202 formed in or on the substrate 201, the at least one optical waveguide 202 being adjacent to the periodic structure portion 206; and at least one optical resonator 203 formed in or on the substrate 201, the at least one optical resonator 203 being formed in a position away from the optical waveguide 202, with at least one hole 2051 among the plurality of holes 2050 and 2051 of the periodic structure portion 206 being interposed between the optical resonator 203 and the optical waveguide 202. The plurality of holes 2050 and 2051 of the periodic structure portion 206 include a hole 2050 having a depth different from a depth of the at least one hole 2051 interposed between the optical waveguide and 202 the optical resonator 203.