To provide a heater control/protection circuit stopping the operation of a heater before the temperature becomes abnormally high when a drive circuit fails and capable of informing the user of the failure of the drive circuit.

When a heater drive circuit 3 fails, the output of the heater drive circuit 3 and the output of a heater control circuit 2 become the same logic, i.e., the same logical signal is inputted to two inputs of a monitor circuit 4, and a high-level signal is outputted from the monitor circuit 4. The PNP transistor 51 of a power supply cutoff circuit 5 is turned off, and the current flowing in a heater 1 is cut off to stop the operation of the heater 1. Upon receiving the high-level signal of the monitor circuit 4, the NPN transistor 62 of an alarm circuit 6 is turned on to light an LED 61, and the failure is shown to a user.