Provided is a short-circuit isolator capable of earlier detection of recovery from short circuit of a disconnected line and reconnecting the line. The short-circuit isolator includes: a switch for switching a connection state between a primary signal line and a secondary signal line; a short-circuit monitor circuit which is connected to a primary wiring of the switch through a resistor as a current limiting section and connected to a secondary wiring of the switch, for detecting short circuit when a voltage of the secondary signal line is lower than a short-circuit detection threshold and detecting recovery from the short circuit when the voltage of the secondary signal line is higher than a short-circuit recovery threshold which is a voltage value lower than the short-circuit detection threshold after the short circuit is detected; and a switch control section for turning off the switch when the short circuit is detected by the short-circuit monitor circuit and turning on the switch when the recovery from the short circuit is detected by the short-circuit monitor circuit.