There is provided a discharge lamp lighting apparatus including a dimmer circuit which is provided with a control means to dynamically adjust screen brightness according to an input signal, and a control means to adjust screen brightness based on a user's operation. The dimmer circuit includes: an amplitude adjusting circuit to superpose a first dimming control signal composed of a DC voltage onto a second dimming control signal composed of a pulse width modulation signal; an integration circuit to integrate an output of the amplitude adjusting circuit; and a comparison circuit to compare an output of the integration circuit with a triangular wave having a predetermined frequency thereby generating a dimming signal, wherein a burst dimming mode is performed according to the dimming signal.