A novel method for detection the gear wear fault according to impulse response wavelet transform is presented. The continuous wavelet transform is widely recognized as an effective technique for rotating machine fault detection using vibration signal since it can be used to detect both stationary and transitory signals. This advantage makes it very suitable for the detection of singularity generated by localized damage in gearbox. In this study, the impulse response wavelet time-frequency joint representation is used to diagnose the gear wear fault. The experimental result shows that impulse response wavelet time-frequency joint representation is a sensitive indicator of the existence of damage in the gearbox.