A discharge lamp lighting apparatus for supplying high frequency high voltage to an excimer discharge lamp comprises a boasting transformer having a core, a secondary side coil and a pair of primary side coils; a DC power source; and switching elements, wherein a duty ratio of an electrically conductive period to an operational cycle of each of the switching elements is 30% or less, a turn ratio of the secondary side coil to each of the primary side coils is 25 or less, a difference between a first length of a first axial direction area where each of the primary side coils are wound, and a second length of a second axial direction area where the secondary side coil is wound, is 18% or less of the first length or the second length, and a leakage inductance associated with magnetic coupling between the primary side coils and the secondary coil is 0.2% to 0.7% of a primary side coil inductance.