In a risk determination method: moving body information, in which accompanying information that indicates the current position of a moving body and a current-position image that indicates a situation around the moving body at the current position are included in correspondence to each other, is obtained; and, if risk occurrence information corresponding to the current position indicated in the accompanying information included in the moving body information is not stored in a risk occurrence information manager and risk occurrence information corresponding to a position other than the current position is stored in the risk occurrence information manager, a degree of risk at the current position is determined on the basis of a similarity between the current-position image included in the moving body information and a risky-position image included in at least one piece of risk occurrence information stored in the risk occurrence information manager.