PURPOSE: To make accurate inspection for an air controller performable, by comparing each pressure signal at an outlet and an inlet of the air controller installed in an emergency generating set with the preset pressure rising curve, and detecting whether there is anything unusual or not.

CONSTITUTION: When a start signal is emitted, after the elapse of a set time at a clock unit 21, first each output of pressure detectors 4A and 4B installed in a port of an air controller is read at a controller 22, and comparison with the preset pressure displacement value takes place. Next, a difference made by this comparison is compared with the specified value, and when the difference is larger than the specified value, inspection failure output is generated there. On the other hand, in time of normality, that is, the difference is smaller than the specified value, successively whether the above-mentioned inspection reaches to the specified frequency or not is discriminated, and when reaching the specified frequency, inspection comes to completion. And, according to the said inspection output, a recording device 24, a CRT device 23 and an alarm device 25 are operated.