A physiological state determination device (10, 110, 400) includes a facial change information acquisition unit (20, 120, 415, 442), a facial change information decomposition unit (30, 130, 443), and a physiological state determination unit (200, 445). The facial change information acquisition unit (20, 120, 415, 442) acquires facial change information indicating time-series changes in facial data of a subject. The facial change information decomposition unit (30, 130, 443) decomposes the facial change information into a plurality of components by singular value decomposition, principal component analysis, or independent component analysis. The physiological state determination unit (200, 445) determines the mental or physical physiological state of the subject on the basis of a determination component extracted from the plurality of components.
