To reduce the number of input ports used for monitoring anomalies of a plurality of fans, restrain addition of hardware for identifying an abnormal electric fan, and avoid as far as possible an unusable state of an image-forming device due to fan anomalies.

An abnormal electric fan detector and an image-forming device using the detector include a plurality of energizing means Sw1-8, an OR-gate 79, and an abnormal-fan-identifying means 130. The energizing means Sw1-8 are individually connected to a plurality of fans F1-8 issuing reference signals indicating presence/absence of an anomaly. The OR gate 79 collects the whole of respective reference-signal wires in one monitor signal wire expressing a logical sum of the presence of anomaly in the fans. In the case of the monitor-signal changes from absence to presence of anomaly, the abnormal-fan identifying mens 130 identifies an abnormal fan by energizing the fans partially and sequentially and referring to the monitor signal. The identifying means 130 identifies the abnormal fan by driving the fans one by one, or by dividing the fans sequentially into two groups. Imaging conditions are limited by dealing with the abnormal fan.