An isolated gate driver has: a register that stores the adjustment data read from a non-volatile memory; a gate driving circuit that drives the gate of a switching element with a characteristic set based on a value stored in the register; a fault detector that performs fault detection for other than the non-volatile memory; an error detection-correction circuit that performs error detection and error correction on the adjustment data written to the non-volatile memory; a first external terminal for output of the result of fault detection; a second external terminal for output of the result of error detection; and a fault controller that, if a one-bit error is detected in the adjustment data, brings the second external terminal into an error-indicating output state and continues with normal operation of the gate driving circuit and, if a two-or-more-bit error is detected in the adjustment data, forcibly stops the gate driving circuit.