Abstract: In addition to reliably protecting the privacy of individuals, it is possible to display a monitoring image from which a congested situation in a facility may be intuitively grasped. The monitoring device of the present disclosure includes first processing unit that performs image processing for reducing identifiability of an object appearing in a captured image on the captured image captured by imaging unit, second processing unit that detects a moving object from the captured image to generate a mask image corresponding to the image area of the moving object, and image output controller that generates and outputs the monitoring image on which the mask image generated by second processing unit is superimposed on the identifiability-reduced image generated by first processing unit.