A method and an apparatus for controlling a privacy mask display includes a monitoring camera which is if tilted and its tilt angle becomes greater than 90.degree. when a privacy mask to mask a specific target object in a captured image frame is displayed, an image and the privacy mask in the frame are rotated 180.degree. with respect to the CCD center axis, and the optical center axis stored in the apparatus is also rotated 180.degree. with respect to the CCD center axis. Afterwards, if the zoom ratio of the monitoring camera changes, the size and position of the privacy mask are adjusted relative to the optical center axis rotated 180.degree. with respect to the CCD center axis. It is therefore possible to freely perform zooming and tilting operations without danger of exposing the privacy-protected target object even under the condition that the optical center axis and the CCD center axis of the monitoring camera do not coincide.