To provide a system for monitoring the inside of a multistory parking garage tower capable of surely confirming the presence or absence of a person in a parking garage in an automated multistory parking garage.

This system comprises an imaging means 20 for imaging a specified area including the entire side surfaces of a vehicle stored in the storage acceptance part of the multistory parking garage and a safety judgment means 30 for judging whether the person is present or not in the multistory parking garage by analyzing the image obtained by the imaging means 20. For the areas of the imaging area including the vehicle nearer the imaging means 20, the safety judgment means 30 detects a variation with a lower sensitivity of pixel change and, accordingly, an image change due to the swing of the vehicle is not detected particularly since the sensitivity is suppressed at the imaged points nearer the imaging means 20, and only an image change according to the movement of the person larger in change than the swing of the vehicle is detected. Thus, it can be surely prevented that the swing of the vehicle is erroneously detected as the motion of the person and recognized erroneously as the presence of the person in the parking lot.