An output correction method for an exhaust gas ingredient-concentration sensor for internal combustion engines. The sensor has two sensor elements having output characteristics different from each other. The sensor elements each produce an output proportional to the concentration of an ingredient in exhaust gases emitted from the engine. The sensor controls the air-fuel ratio of a mixture supplied to the engine to a desired air-fuel ratio by the use of an output from at least one of the sensor elements. First, it is determined whether or not the difference between the desired air-fuel ratio and an actual air-fuel ratio represented by the output of at least one of the sensor elements is smaller than a predetermined value. Then, an output value of one of the sensor elements is corrrected based on an output value of the other of the sensor elements when it is determined that the difference is smaller than the predetermined value.