To improve uniformity in brightness on a light-emitting face with high efficiency and at a low cost in a discharge lamp lighting device suitable for a backlight.

Inverter circuits having step-up transformers T1, T2 on the output side of a full bridge circuit are constituted, respectively, in first and second substrates PB1, PB2, inverter outputs of the respective substrates PB1, PB2 are approximately synchronized with each other, and against a plurality of members of discharge lamps 4a, 4b arranged in parallel, a first discharge lamp 4a is connected to a high voltage terminal of the step-up transformer T1 mounted on the first substrate PB1 and to a low voltage terminal of the step-up transformer T2 mounted on the second substrate PB2, and the other discharge lamp 4b is connected to the low voltage terminal of the step-up transformer T1 mounted on the first substrate PB1 and to the high voltage terminal of the step-up transformer T2 mounted on the second substrate PB2, and discharge lamps 4a, 4b are lighted on at a high frequency.