An arc discharge detecting circuit includes; a voltage dividing part which divides a driving voltage provided to a light source, a detecting part which includes a loop-shaped wiring spaced apart from the voltage dividing part and which detects a current corresponding to an arc discharge flowing through the voltage dividing part using a coupling capacitance generated between the loop-shaped wiring of the detecting part and a wiring of the voltage dividing part, and an output part connected to the detecting part to output a detection voltage corresponding to the arc discharge. Accordingly, the arc discharge detecting circuit may improve a sensitivity of detecting an arc discharge as a current source type using the coupling capacitors, a design may be simplified, and manufacturing costs may be decreased.