PURPOSE: To make heating means for a detection part to be prevented from a thermal deterioration by increasing an electricity energizing quantity to the heating means for the detection part from electric power supplying means in accordance with a change to the increasing side of a fuel injection quantity for a parameter which is detected in parameter detecting means.

CONSTITUTION: By supplying the electric power to the heating means M4 for the detection part from the power supplying means M5, the means M4 is heated and a soot in a smoke stuck to the detection part M3 is burnt out. Further, the energizing quantity to the means M4 is controlled by the energizing quantity control means M7 in accordance with the parameter which is detected by the parameter detecting means M6 and reflected with the fuel injection quantity to an internal-combustion engine M1, that is, controlled in such a manner that the energizing quantity to the means M4 is increased when the parameter is changed to the increasing side of the fuel injection quantity. So, when the parameter value such as the fuel injection quantity of the engine M1 is made to be small is detected, the heating temperature of the means M4 is lowered, and as the parameter value is changed to the increasing side of the fuel injection quantity, the heating temperature of the means M4 is elevated, thereby the means M4 is prevented from the thermal deterioration.