A control apparatus for a heater is equipped with a high-side wiring line that is connected between the heater and a power supply, a low-side wiring line that is connected between the heater and a grounded portion, a sense wiring line that is connected between the heater and a heater electrode of the heater, and a fault detector for detecting a fault in any one of the wiring lines respectively connected to the heater. The fault detector is configured to identify a mode of a fault that has occurred and a location where the fault has occurred, based on a high-side voltage, a low-side voltage, a sense voltage, a high-side current and a low-side current.