IN-VEHICLE RADIATION HEATER CONTROL APPARATUS

An in-vehicle radiant heater control apparatus includes: a temperature detection device (S345, S435, S435A) for a heater (30a - 30d) in a vehicle compartment; a first switch element (50) connected in series to the radiant heater between a power supply and a ground; a temperature control device (S200 - S280) controlling the first switch element that the heater temperature approaches a target temperature; a resistive element (52, 70) having one electrode (52b, 70b) connected to one electrode (31a) of the heater; an inter-electrode voltage detection device (S340, S430, S430A) for the resistive element; and a resistance calculation device (S340, S430, S430A) repeatedly obtaining a heater resistance of the radiant heater based on a voltage between the other electrode (52a, 70a) of the resistive element and the other electrode (31b) of the heater, a detected resistance voltage, and a resistance of the resistive element. The temperature detection device obtains the heater temperature based on the heater resistance.