A device for protecting an inverter include a first power switch configured to be turned on when a first voltage signal from a first switch of a safety relay is applied thereto; a second power switch connected in series with the first power switch, wherein the second power switch is configured to be turned on when a second voltage signal from a second switch of a safety relay is applied thereto; and a power line for connecting the first power switch and the second power switch to each other in series and for connecting the series of the first power switch and the second power switch to a buffer of the inverter, wherein a third voltage signal is applied via the power line to the buffer.