A device for driving a load comprising first and second motors (322, 323) in an outdoor unit of an air conditioner, wherein said first motor drives a first compressor in the outdoor unit and said first compressor compresses a cooling medium, the device comprising: a power source switch having an input side connected to a power source and an output side; an inverter circuit (312, 313, 314) including a diode bridge and a first switching circuit switching a DC voltage outputted from said diode bridge and outputting said voltage to said first motor supplied with power from said inverter circuit (312, 313, 314); a first control circuit connected to said output side of said power source switch and supplied with operating power upon connection of said power source switch; a second control circuit including said inverter circuit (312, 313, 314) generating power to be supplied to said first motor from power supplied from said power source, a second control switch interposed between said power source switch and said inverter circuit (312, 313, 314) and connected/disconnected according to normality/abnormality of said first motor; a third control circuit having a second switching circuit switching said DC voltage of said inverter circuit (312, 313, 314) and outputting said voltage to said second motor to supply said second motor with operating power, and driving said second motor based on a second control command (CNTL2) from said first control circuit; wherein said first control circuit generates a second switching command to disconnect a second control switch when an abnormality in pressure occurs in said first compressor, a first control switch (304, 305) is connected to said output side of said power source switch and connected/disconnected under a first switching command from said first control circuit; wherein the second control circuit is supplied with power upon connection of both of said power source switch and said first control switch (304, 305) and drives said first motor under a first control command (CNTL1) from said first control circuit. a power source switch having an input side connected to a power source and an output side; an inverter circuit (312, 313, 314) including a diode bridge and a first switching circuit switching a DC voltage outputted from said diode bridge and outputting said voltage to said first motor supplied with power from said inverter circuit (312, 313, 314); a first control circuit connected to said output side of said power source switch and supplied with operating power upon connection of said power source switch; a second control circuit including said inverter circuit (312, 313, 314) generating power to be supplied to said first motor from power supplied from said power source, a second control switch interposed between said power source switch and said inverter circuit (312, 313, 314) and connected/disconnected according to normality/abnormality of said first motor; a third control circuit having a second switching circuit switching said DC voltage of said inverter circuit (312, 313, 314) and outputting said voltage to said second motor to supply said second motor with operating power, and driving said second motor based on a second control command (CNTL2) from said first control circuit; wherein said first control circuit generates a second switching command to disconnect a second control switch when an abnormality in pressure occurs in said first compressor, a first control switch (304, 305) is connected to said output side of said power source switch and connected/disconnected under a first switching command from said first control circuit; wherein the second control circuit is supplied with power upon connection of both of said power source switch and said first control switch (304, 305) and drives said first motor under a first control command (CNTL1) from said first control circuit.