PURPOSE: To provide the binary image display device which can make a binary artificially multi-gradational display of a color still picture or color moving picture and reduces the movement of a view point and the cost of a system by clearly displaying an image, generated by making the artificially multi- gradational display of a color image, on one display unit together with the binary image.

CONSTITUTION: A terminal 1 of a TV conference system is connected to a line through a network interface part 3. When color still picture information is received from an opposite terminal, encoded data from a multi-media multiplexing and demultiplexing part 4 are stored in the buffer of a still picture encoding and decoding part 6, only brightness information is extracted by a system control part 2 from the encoded data, and the decoded data are stored in another buffer. The data are processed by dither conversion into artificially multi-gradational display data and the color image is displayed on an LCD, which is arranged in the conference system and makes a binary image display, with multi-gradations.