A discharge lamp lighting apparatus includes switching elements to pass a current to a primary winding of a transformer and a capacitor, an oscillator to generate a triangular signal, an error amplifier to amplify an error voltage of a voltage corresponding to a current passed through a discharge lamp and receive a burst dimming signal that is a pulse signal to intermittently supply power to the discharge lamp, comparators to compare the error voltage with the triangular signal and generate PWM control signals that turn on/off the switching elements, respectively, a clamp circuit to clamp an output from the error amplifier so that the output from the error amplifier may not drop below a lower limit value of the triangular signal during an OFF period of the burst dimming signal, and breaking circuits to block the PWM control signals during the OFF period of the burst dimming signal.