An abnormal current cut off circuit for creating a circuit break when an abnormal current flows in a circuit such as a print head driver circuit for a printer. When a driver section 3 is being driven by a power supply circuit 1, the power supply is provided to a driver circuit 2 which drives the driver section 3 via a transistor 5 which is connected in the power supply line and which is turned on by a transistor 7. When the device goes into a standby state, the transistor 5 is turned off, so that the current is supplied to the carriage motor a and the Line feed motor b within the driver section 3 via the fuse 4 and the diode 6 which are connected in parallel with the transistor 5. If an abnormal current then flows during the standby state, the fuse 4 will be broken, and transistor 7 will be turned off so that transistor 5 will also be turned off which ensures that the power supply line is cut completely.