Power supply control system for a gas sensor used in a heating

Heating control device a gas concentration sensor (15) having a sensor element (30) which uses a solid electrolyte, and a heater (39) for heating the sensor element (30) on an activated state of a sensor element resistance determining circuit (20, 25, 32, 33) adapted to determine the element resistance of the sensor element (30), a heater control variable determining circuit (20) adapted to calculate an integral term by adding an integral constant to a deviation of a detected value of the element resistance value from a target value and also for calculating a heating control variables using the integral term, and a heater control circuit (26) which operates to control a heating power calculated by the heater control variable, characterized in that the heater control variable determining circuit (20) is adapted to impose a limit on the increase in the value of the integral term, to the resistance value of the sensor element (30) reaches a preselected value in the course of activation of the sensor element (30) to calculate the heater control variable pick up and the limit on the integral term after the element resistance value has reached the pre-selected value to calculate the heater control variable.