An information processing apparatus is configured to correctly detect a polygon face of a mirror being scanned even when noise occurs in a synchronization signal. The information processing apparatus is connected to an image forming apparatus including a laser light source configured to receive image data and output light; a photosensitive member; a polygon mirror, which has a plurality of reflection faces, and is configured to rotate to deflect a laser beam through use of the plurality of reflection faces, to thereby scan the photosensitive member; and a generator configured to generate a marking BD (beam detection) signal based on the deflected laser beam. The information processing apparatus receives a marking signal and determines whether or not the received marking signal is a signal corresponding to a specific reflection face among the reflection faces of the polygon mirror.