The purpose of the present invention is to provide an image monitoring system which can be used in a place where a network cannot be established and has excellent portability. When an image is captured during the daytime or in a bright place, a camera (10) is equipped with a near-infrared cut filter, captures an image of a subject, and outputs a color image. On the other hand, when an image is captured during the nighttime or in a dark place, the near-infrared cut filter is removed from the camera (10), an LED light (11) irradiates the subject with near-infrared light in synchronization with the shutter speed of the camera (10), and the camera (10) captures an image of the near-infrared light reflected by the subject and outputs a monochrome image. The image outputted from the camera (10) is inputted to a recording device via a dedicated cable.