A state determination apparatus 100 determines the state of a structure 200. The state determination apparatus 100 includes a measurement unit 10 configured to measure a deflection amount and a surface displacement amount in each of a plurality of target regions that are preset on the structure 200, a feature value calculation unit 20 configured to calculate, for the respective target regions, feature values each indicating a relationship between the deflection amount and the surface displacement amount, using the measured deflection amount and surface displacement amount, a spatial distribution calculation unit 30 configured to calculate a spatial distribution of the feature values using the feature values calculated for each of the target regions, and a degradation state determination unit 40 configured to determine a degradation state of the structure 200 based on the spatial distribution of the feature value.