1. An information processing apparatus comprising: a building unit configured to build a temporal feature amount change model by extracting feature amounts from a plurality of medical images obtained by imaging the same object in different periods; a readout unit configured to read out, from a database, case data containing a plurality of medical images obtained by imaging the same object in different periods; an acquisition unit configured to acquire inspection data containing a plurality of medical images obtained by imaging an object to be inspected in different periods; an interpolation unit configured to interpolate, by using the model, either of feature amounts extracted from the plurality of medical images contained in the case data and feature amounts extracted from the plurality of medical images contained in the inspection data; a calculation unit configured to calculate similarities between the plurality of medical images contained in the inspection data and the plurality of medical images contained in the case data by using the feature amounts interpolated by said interpolation unit; and an output unit configured to output case data selected based on the calculated similarities.