A fuel injection amount control apparatus controlling an amount of fuel supplied to an internal combustion engine is disclosed. An intake passage extends from the engine, and the intake passage is branched into a plurality of branch passages in an upstream section. The apparatus includes a plurality of intake air temperature sensors and an ECU. Each of the intake air temperature sensors is provided in one of the intake passages and detects an intake air temperature in the corresponding intake passage. The ECU selects an intake air temperature that most directly expresses the engine state or the environment from the intake air temperatures detected by the intake air temperature sensors. The ECU controls the amount of the fuel supplied to the engine by using the selected intake air temperature.