To stabilize an air-fuel ratio at a time of starting an internal combustion engine and to reduce emission, by correcting a starting time fuel injection amount depending on changes in air amount at the time of starting the engine.

This fuel injection amount control apparatus controls the starting time fuel injection amount of the internal combustion engine, in which a starting time air amount is corrected based on an idling time required air amount of the air amount required to keep a revolution speed of the engine during idling after warm-up of the engine. The fuel injection amount control apparatus comprises: a calculating means for calculating the starting time fuel injection amount TAUST based on a predetermined starting time engine operational state other than the air amount; and a correcting means for correcting the starting time fuel injection amount TAUST calculated by the calculating means based on a ratio KGAIDL of a present idling time required air amount QG to a idling timing required air amount QGST in a new car.