A light driving apparatus includes a first rectifying unit for receiving AC power and rectifying the AC power into DC, a switching element controlled to turn on or off by a control signal, a transforming unit having a transformer and an inductor connected to a primary side of the transformer in parallel, a second rectifying unit for rectifying a secondary side output of the transforming unit and supplying an output voltage thereof to a LED unit, and a control unit provided in the primary side to give a constant-current control function so that a secondary side output is maintained consistently. According to the present disclosure, it is possible to simplify the circuit structure of the secondary side and improve the efficiency by controlling the secondary side current at the primary side without secondary side feedback information.