The present invention relates to a method for producing a photonic crystal device having a photonic crystal structure which can be used in photonic crystal devices such as optical waveguides, resonators, filters, antennas and Smith-Purcell free electron lasers which can be employed in a desired electromagnetic waveband by application of semiconductor processing technology and of an anisotropic wet process which uses the crystallization direction (100) of a silicon wafer; for producing a photonic crystal device which comprises a photonic crystal part having a periodic array of silicon crystals having a predetermined form and a covering part for reducing optical losses in the axial direction to be used as an optical waveguide or a resonator, thereby to be capable of being applied in a desired electromagnetic band; and which can have the conductive photonic-crystal characteristics by not coating the silicon crystal with an electrically conductive material and the metal photonic-crystal characteristics by coating the silicon crystal with an electrically conductive material. This production method makes it possible to mass-produce photonic crystal structures of relatively low cost and substantial height within a short time.