A fatigue judgment system and a fatigue judgment method, which can decide the degree of fatigue of a driver precisely without imposing a spiritual burden on the driver. The fatigue judgment system comprises a unit (e.g., a seat pressure sensor (4)) for detecting the position fluctuations of a driver (2), and a unit (e.g., a fatigue judgment unit (13A)) for judging it from the position fluctuations (including the frequency of fluctuating the position) detected by the unit (4) whether or not the fatigue of the driver (2) exceeds a predetermined level (or a threshold value or more).
