In order to evaluate the risk of a slope collapsing before installing a sensor, a risk determination device 100 comprises: a first calculation unit 110 that calculates a parameter to indicate the condition of soil on the basis of the relationship between the condition of the soil constituting a slope and the moisture condition of the soil and virtual data for the moisture condition； a second calculation unit 120 that calculates a safety factor for the slope using the calculated parameter； and a determination unit 130 that determines the risk of the slope collapsing on the basis of the moisture condition in which the calculated safety factor is below a threshold and the moisture condition of the soil based on the virtual data when the moisture is saturated.
