PURPOSE: To properly maintain exhaust emission especially at the time of a cold engine by accurately performing temperature characteristic correction of an air-flow sensor.

CONSTITUTION: An engine temperature detection means E for detecting the temperature of an engine and a learning control means F for executing learning of a control value by a learning means per range set in response to the temperature of the engine are provided in an engine controller provided with a hot wire type intake air quantity detection means A, an air-fuel ratio detection means B for detecting an air-fuel ratio, an air-fuel ratio control means C for feedback-controlling a fuel supply quantity in response to the intake air quantity so that the air-fuel ratio detected by the air-fuel ratio detection means B may match a target air-fuel ratio, and a learning means D for learning and renewing the control value of the feedback-control sequentially. In this constitution, the learning of the control value is carried out per range set in response to the temperature of the engine andd thereby accurate air-fuel ratio control under a condition where influence of variation of output characteristic of an air-flow sensor is reduced to the possible minimum level.