A watching assistance system that assists watching over a subject on a bed includes an image acquisition unit configured to acquire an image captured by an imaging device, a criterion storage in which a criterion for determining a dangerous state are previously set for each of a plurality of determination regions set based on a region of the bed in the image, a detector configured to detect the subject from the image acquired by the image acquisition unit, a state recognition unit configured to recognize a state of the subject detected by the detector, a determination unit configured to determine a danger degree of the state of the subject recognized by the state recognition unit using the criterion for the determination region corresponding to a position at which the subject is detected by the detector, and an output unit configured to provide notification according to the danger degree determined by the determination unit.