To provide a background image concealing method which, when imaging a person and transmitting the image data, is capable of concealing the background of the person by an inexpensive configuration.

The background image concealing method comprises: an imaging process in which imaging means images a subject and outputs the image data; a face detection process in which face detection means detects a face region from the image data; a comparison process in which brightness comparison means compares brightness between the detected face region of the image data and its background region to determine whether brightness of the background region is larger than that of the face region by a predetermined amount or more; an exposure setting process in which, if the brightness of the background region is larger than that of the face region by the predetermined amount or more, exposure control means sets the exposure of the imaging means to be higher; and a transmission process in which communication means transmits to an opposite party the image data obtained by imaging with the set exposure by the imaging means in the imaging process.