The present invention aims at providing an image reading device and an image forming apparatus including a light guiding body having a first emission surface and a second emission surface. A color copy machine includes a luminescence portion including: LEDs composed of a plurality of dot-shaped luminescence members disposed at predetermined intervals in a main scanning direction and/or an elongated luminescence member that is formed to extend in the main scanning direction; and a light guiding body that is disposed between the LEDs and an original, and has a light incidence portion disposed on a side to the LEDs and an emission portion disposed on a side to the original. The emission portion has a first emission surface and a second emission surface that is formed on a different plane from a plane including the first emission surface.