An object-characteristic determination device includes a calculation unit and a determination unit. The calculation unit calculates a first feature value and a second feature value differing from the first feature value according to a first signal at a first frequency and a second signal at a second frequency. The first signal and the second signal are received by a reception unit after passing through the object. The first feature value and the second feature value represent features of the first signal and the second signal. The determination unit determines a property of the object on the basis of a difference in the first feature values of the first signal and a difference in the second feature values of the second signal, a relationship between a plurality of properties of the object, and a plurality of differences in the first feature values and a plurality of differences in the second feature values.