There is provided a LED array driving apparatus for driving a light emitting array having a plurality of LEDs connected to one another, including: a DC-DC converting part; a current/voltage detecting part detecting a magnitude of a first current flowing through a switching transistor of the DC-DC current converting part to correspondingly output a first current detection voltage, detecting a magnitude of a both-end voltage of the LED array to correspondingly output a LED array detection voltage, and detecting a magnitude of a current flowing through the LED array to correspondingly output a second current detection voltage; and a constant current controlling part controlling an on/off duty of the switching transistor according to the magnitude of the first current detection voltage, the second current detection voltage and the LED array detection voltage detected by the current/voltage detecting part.