An illumination device comprising: a light source configured to generate primary light having a Gaussian intensity distribution; an beam homogenizer optical member configured to convert the primary light to generate secondary light having a top-hat type intensity distribution to control an emission angle and light distribution of the secondary light; a wavelength converter (14, 31, 32) configured to receive the secondary light from a light-receiving surface thereof, generate tertiary light including transmitted light of the secondary light and wavelength-converted light in which a wavelength of said secondary light has been converted, and emit the tertiary light from an emission surface of the wavelength converter (14, 31, 32), wherein the transmitted light of the secondary light included in tertiary light maintains the same light distribution characteristics as the light distribution characteristics of the secondary light generated by the beam homogenizer optical member, in which the wavelength-converted light and the transmitted secondary light are mixed with each other at the same intensity ratio in any of the radiation directions from the emission surface; and an antenna array having a plurality of optical antennas (22A, 23A) formed on said emission surface of said wavelength converter (14, 31, 32) and arranged at a period larger than an optical wavelength of the secondary light in said wavelength converter (14, 31, 32); wherein said light-receiving surface of said wavelength converter (14, 31, 32) has an irradiated region irradiated with the secondary light and a peripheral region provided around said irradiated region, said emission surface of said wavelength converter (14, 31, 32) has a first emission region corresponding to the irradiated region of the light-receiving surface and a second emission region corresponding to said peripheral region, and said antenna array includes a first sub-array comprising a plurality of the optical antennas arranged on said first emission region of said emission surface, and a second sub-array comprising a plurality of the optical antennas arranged on said second emission region and having a larger antenna occupancy ratio per unit area than that of said first sub-array. a light source configured to generate primary light having a Gaussian intensity distribution; an beam homogenizer optical member configured to convert the primary light to generate secondary light having a top-hat type intensity distribution to control an emission angle and light distribution of the secondary light; a wavelength converter (14, 31, 32) configured to receive the secondary light from a light-receiving surface thereof, generate tertiary light including transmitted light of the secondary light and wavelength-converted light in which a wavelength of said secondary light has been converted, and emit the tertiary light from an emission surface of the wavelength converter (14, 31, 32), wherein the transmitted light of the secondary light included in tertiary light maintains the same light distribution characteristics as the light distribution characteristics of the secondary light generated by the beam homogenizer optical member, in which the wavelength-converted light and the transmitted secondary light are mixed with each other at the same intensity ratio in any of the radiation directions from the emission surface; and an antenna array having a plurality of optical antennas (22A, 23A) formed on said emission surface of said wavelength converter (14, 31, 32) and arranged at a period larger than an optical wavelength of the secondary light in said wavelength converter (14, 31, 32); wherein said light-receiving surface of said wavelength converter (14, 31, 32) has an irradiated region irradiated with the secondary light and a peripheral region provided around said irradiated region, said emission surface of said wavelength converter (14, 31, 32) has a first emission region corresponding to the irradiated region of the light-receiving surface and a second emission region corresponding to said peripheral region, and said antenna array includes a first sub-array comprising a plurality of the optical antennas arranged on said first emission region of said emission surface, and a second sub-array comprising a plurality of the optical antennas arranged on said second emission region and having a larger antenna occupancy ratio per unit area than that of said first sub-array.