This disclosure relates to bioelectric signal detecting circuits, lead wire detecting circuits and medical devices. The lead wire detecting circuit may include a reference voltage generator, at least one comparator, and a logic control module, wherein input ends of the comparator are connected to an output end of the reference voltage generator and an signal output end of a lead wire, respectively, for inputting a reference voltage and a lead signal, and the comparator compares the lead signal with the reference voltage and changes an output voltage at an output end of the comparator according to a comparison result wherein an input end of the logic control module is connected to the output end of the comparator, and the logic control module determines whether the lead wire is in a connected state or disconnected state by the output voltage at the output end of the comparator.
