Disclosed is a fault diagnosis apparatus for an airflow meter for determining that the airflow meter has a fault when a divergence ratio, i.e., a divergence value of an estimated intake-air quantity with respect to an actual intake-air quantity obtained by the airflow meter is greater than a fault-determination reference value determined based on a rotation speed of an internal combustion engine. The apparatus determines that the airflow meter is normal when the engine speed is higher than or equal to a predetermined speed under a specific condition that the divergence value is less than or equal to the reference value, and also maintains a current determination result when the engine speed is less than the predetermined speed under the specific condition, thereby determining, based on the engine speed, whether the airflow meter is normal or the current determination result is maintained, and thus improving the fault-diagnosis accuracy.