According to one aspect of the present invention, there is provided an illumination apparatus 110 including a laser source 11, a two dimensional diffraction optics 13 on which laser beam from the laser source is made incident, a rectangular rod 14 on which diffraction beams from the two dimensional diffraction optics 13 are made incident and through which incident beams travel while repeating total reflection, and a galvano mirror 12 changing an incident position of the diffraction beams from the two dimensional diffraction optics 13 in an incident end surface of the rectangular rod 14.