To suppress power consumption of a discharge lamp lighting system at abnormalities of a discharge lamp.

A lamp abnormality detecting circuit 14 detects a state of the discharge lamp LA, and outputs an abnormal lamp detection signal (S110). An abnormal lamp detection determination part 62 determines the abnormal lamp detection signal (S111), and, if the lamp is in an abnormal state, an inverter circuit 3 stops oscillation (S113), and at the same time, the abnormal lamp detection determination part 62 writes in an information showing that an abnormal lamp is mounted, in a non-volatile memory 15, and a microcomputer 6 stops processing (S115). Later, the microcomputer 6 starts up (S101), and a drive signal generating part 61 determines the information written on the non-volatile memory 15. In the case of an abnormal lamp mounting state, the microcomputer 6, in stead of lighting the discharge lamp LA, stops processing (S115).

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