An illumination apparatus applies uniform light beams having a fixed angle distribution as illumination light to obtain illumination having a uniform light distribution. The illumination apparatus includes a light source and an optical member having an incidence surface on which light is made incident and an emission surface through which the light made incident on the incidence surface is emitted as illumination light. The optical member further has a light direction conversion surface disposed so as to face the emission surface for, while regulating a traveling direction of light made incident on the incidence surface within the optical member, and guiding the light to the emission surface. The optical member also has a plurality of prism-like portions each having a total reflection surface and a reincidence surface continuously formed in the light direction conversion surface.