A driver condition estimating device includes circuitry configured to measure movement of the head of a driver output from a driver camera that photographs the driver and detect a sign of abnormality of the driver from the movement of the head. The circuitry determines existence of the sign of abnormality of the driver by calculating a periodic feature amount from time series data showing movement of the head of the driver, calculating coherence between the movement of the head of the driver and lateral acceleration acting on the head of the driver, calculating time series variation patterns from the obtained periodic feature amount and the obtained coherence, and comparing the obtained time series variation patterns with a predetermined threshold.