Disclosed herein is a backlight inverter for a U-shaped lamp which is capable of detecting an abnormal state of an inverter circuit. The backlight inverter comprises a driver for supplying first and second transformer drive voltages in response to an operation control signal and cutting off the supply of the transformer drive voltages in response to a shutdown control signal, first and second transformers for boosting the transformer drive voltage in a turn ratio between primary and secondary windings thereof and supplying the resulting drive voltage to the U-shaped lamp, first and second voltage detectors for detecting voltages across the secondary windings, respectively, first and second current detectors for detecting currents flowing through the secondary windings of the first and second transformers, respectively, an inverter abnormal state detector for detecting an abnormal state of the inverter, and a driver controller for controlling a normal operation or shutdown of the driver.