Disclosed is a device for detecting a phase loss in an output current in an inverter. The device includes: an output current detection unit for detecting two phases output currents from two signals output from two shunt-resistors connected to two phases legs respectively; an output current calculation unit for calculating an output current of one remaining phase using the detected two phases output currents; and an output phase loss detection unit configured for detecting an output phase loss when the calculated output current is within a current band corresponding to the output phase loss or when the calculated output current has a magnitude equal to and a sign opposite to one of the detected two phases output currents.