A state determination device includes a myopotential measurement unit configured to measure a myopotential of a surface of the body, a myopotential integrated value calculation unit configured to calculate a myopotential integrated value by integrating, with time, the myopotential measured by the myopotential measurement unit for a measurement period at predetermined measurement intervals, and a fatigue determination unit configured to determine presence/absence of fatigue of the body based on a size of the myopotential integrated value calculated by the myopotential integrated value calculation unit, and a change amount of the myopotential integrated value.
