DEGRADATION STATE DETERMINATION METHOD AND APPARATUS

A degradation state determination method for determining a degradation state of a target object based on a color of an indicator attached to the target object includes generating a color change database including data indicating a relationship between a change in color of the indicator and an amount of a degradation factor that causes the target object to degrade, selecting a color to be used for the indicator so that the amount of the degradation factor can be identified, acquiring an image of the indicator attached to the target object and extracting a color component from the image (S27), and determining, based on the color change database and the extracted color component, the degradation state of the target object using a degradation determination model that takes the amount of the degradation factor as an input and outputs an index of the degradation state of the target object (S30).