To provide a signal conversion circuit which can convert a high frequency differential signal to a single end signal, an isolator circuit equipped with the signal conversion circuit, and a signal conversion method.

A signal conversion circuit 10 according to the present invention comprises hysteresis comparators 1, 2 which accept input signals D1 and D2 which are differential signals and a conversion buffer 3. The hysteresis comparator 1 outputs, as a signal E1, the result of magnitude comparison between a potential V1 of the signal D1 and a potential V2 of the signal D2. The hysteresis comparator 2 compares the magnitude between the potential V1 and the potential V2, and outputs the result of the comparison as a signal E2 which is an inverted signal of the signal E1. The conversion buffer 3 converts the signal E1 and the signal E2 to a single end signal F.