A light-emitting-diode (LED) driving apparatus including an AC-DC power conversion stage, a balance circuit and a pulse-width-modulation (PWM) control unit is provided. In the present invention, the LED driving apparatus balances currents flowing through all LED strings by using the balance circuit such that a purpose of current matching is achieved accordingly. In addition, the LED driving apparatus may control the PWM control unit according to an equation between an independent DC output voltage generated by the AC-DC power conversion stage and a control voltage provided by the balance circuit without adopting any boost converter so as to indirectly change a DC output voltage used for directly driving all LED strings and generated by the AC-DC power conversion stage. In this way, the purpose of low cost and high efficiency can be achieved accordingly.