Injector Diagnosis Device and Injector Diagnosis Method

An injector diagnosis device includes: an engine sound model generator configured to generate a normal engine sound model and an abnormal engine sound model based on the number of cylinders of the engine and a combustion pattern of the engine; an operating sound obtainment unit configured to obtain the operating sound of the engine operating with the combustion pattern; a frequency characteristics calculation unit configured to calculate the frequency characteristics of the operating sound obtained by the operating sound obtainment unit and an injector diagnosis unit configured to diagnose whether or not the injectors have a failure based on the frequency characteristics of the operating sound which is calculated by the frequency characteristics calculation unit and the normal engine sound model and the abnormal engine sound model which is generated by the engine sound model generator