An illumination light communication apparatus includes: a light source which emits illumination light; a power supply circuit for supplying constant current to the light source; a switch which is connected in series to the light source, and intermittently interrupts current which flows through the light source; a signal generating circuit which generates a binary communication signal which controls on and off of the switch to modulate the illumination light; and a current limiting circuit which is connected in series to the light source and the switch, and limits the current which flows through the light source to prevent the current from exceeding a current set value which is variable.