A priority determination system includes: an anomaly obtainer that obtains anomaly data items each indicating anomaly in a corresponding one of moving bodies; a state obtainer that obtains state data items each indicating a state of a corresponding one of the moving bodies; a risk value calculator that calculates, for each of the anomaly data items, a risk value indicating a risk of the anomaly based on a state data item of the corresponding one of the moving bodies; a priority determiner that determines a priority of a task for dealing with the anomaly indicated by each of the anomaly data items, based on the risk value of the anomaly data item; and an outputter that provides output based on a result of the determination.