To provide an optical component capable of enhancing the efficiency of taking light out of a light source and an illumination device using the same.

The illumination device comprises an LED chip 2 being a light source, a sealing resin 3 for sealing the LED chip 2, the optical component 1 provided atop the sealing resin 3 and opposed to a light emission surface of the LED chip 2, and a lighting device for supplying electric power to the LED chip 2. The optical component 1 has an approximately plane-shaped light incident surface 10 on which the light from the LED chip 2 is made incident, and an approximately plane-shaped light exit surface 11 from which the light incident from the light incident surface 10 is taken outside. The light incident surface 10 and the light exit surface 11 respectively have rough surfaces 12, 13 provided with a number of irregularities within a range where the incident angle of the light incident on each surface is above the critical angle α.

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