Abstract: A feature-amount generation device that includes an extraction unit that generates a gait waveform for one gait cycle from time-series data of sensor data related to a motion of a foot, extracts a feature amount from the generated gait waveform, and extracts a gait phase cluster by integrating a plurality of temporally continuous gait phases from each of which a feature amount is extracted, and a generation unit that generates a feature amount of the gait phase cluster using a preset feature-amount constitutive expression, and generates feature-amount data in which the plurality of gait phases constituting the gait phase cluster and the feature amount of the gait phase cluster are associated with each other.