A driver state determination device (10, 110, 400, 400A, 400B) includes a facial change information acquisition unit (20, 120, 415, 442), a facial change information decomposition unit (30, 130, 443), and a driver 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 (30, 130, 443) unit decomposes the facial change information into a plurality of components 1, 2, 3... by singular value decomposition, principal component analysis, or independent component analysis. The driver state determination unit (200, 445) determines the driver state of the subject on the basis of a determination component extracted from the plurality of components 1, 2, 3....
