A lighting apparatus of high intensity discharge lamp comprises a DC power source, a series connection of a first and a second transistors; a series connection of a first and a second capacitors connected in parallel with the series connection of the transistors; a series connection including at least an inductor and a discharge lamp connected between a connection point of the transistors and another connection point of the capacitors, and a control circuit for switching on and off of the transistors so as to supply electric power to the discharge lamp. A voltage of the first capacitor is set to be higher than that of the second capacitor corresponding to the capacitances of the first and second capacitors. Thus, the pulse height in negative or positive phase of the rectangular alternating voltage applied to the discharge lamp can be increased without increasing the output voltage from the DC power source.