Motion image difference detecting apparatus

In, for example, a teleconference system, a motion image difference detecting apparatus comprises a first memory (8) for storing first data of a motion image signal corresponding to a first area obtained by dividing the motion image signal, a second memory (12) for storing second data of the motion image signal corresponding to a second area obtained by so dividing the motion image signal, an overlap area of the motion image signal where the first and second areas meet being stored in each of the memories (8, 12), a memory controller (2) for controlling each of the memories (8, 12) so as to store thereinto the image signal of the overlap area, and a detector (6, 10) for detecting a difference between the present frame image and the preceding frame image in the form of block units.