To provide a corrosion inspection method which enables grasping the corrosion state of a measuring target, using a simple work operation.

In the corrosion inspection method, in a state where a sheathing material is attached to the measuring target, counted value related to the moisture amount of the sheathing material is measured by a neutron moisture meter; and only when the counted value is higher than a preset threshold, is the wall thickness of the measuring target measured by an eddy current flaw detector. Accordingly, since the measurement target which is higher than the threshold is specified from among a large number of measuring targets by the neutron moisture meter having a high measuring speed and the measurement of wall thickness may be executed, only with respect to the specified measuring target, a long time is not required for corrosion inspection; and the corrosion state of the measuring target can be grasped by using a simple work operation. Furthermore, since wall thickness is directly measured with respect to the specified measuring target, proper maintenance control can be performed by a simple work operation.