There is provided a light source apparatus including at least one light emitting diode (LED) string including at least one light emitting diode and at least one inductance unit for generating an induced current according to a change in a current applied to the light emitting diode. A main switch controls power applied to the LED string according to an on/off switching operation A capacitor is charged with a voltage of the power applied to the LED string when the main switch is switched on, and applies the charged voltage to the LED string when the main switch is switched off.