A risk managing device for monitoring and managing one or more areas at risk, includes an obtaining module, a setting module, an updating module, a calculating module, and a sorting module. The obtaining module obtains live inspection information of an area. The setting module sets a Severity, Occurrence, and Detection (SOD) score for each failure factor of each safety device. The updating module updates the SOD score of each failure factor of each safety device according to the live inspection information. The calculating module calculates a grey correlation degree of each safety device according to updated SOD score. The sorting module outputs a risk sorting list of the plurality of safety devices of the area according to the grey correlation degree of each safety device. A risk managing method is also provided.