1. An imaging region adjustment device comprising camera terminals, wherein each of said camera terminals includes: a camera which images a virtual imaging region obtained while changing a position of an imaging region within a specific region in a specific period of time; a communication unit operable to send and receive virtual imaging region information indicating the virtual imaging region; and an adjusting unit operable to adjust a position of the virtual imaging region of one's own camera terminal so that a combined region of the virtual imaging regions of said camera terminals completely covers a specific imaging target region, based on the virtual imaging region of one's own camera terminal and virtual imaging regions of the other camera terminals indicated by the virtual imaging region information received by said communication unit, wherein said imaging region adjustment device further comprises a region dividing unit operable to divide, into N regions, a region containing virtual imaging regions of N (≧22) camera terminals among said camera terminals and allocate the respective N divided regions to said N camera terminals, and said adjusting unit is operable to execute the adjustment of the region allocated to one's own camera terminal by said region dividing unit, regarding the allocated region as a new virtual imaging region.