PURPOSE: To provide a fractal image compressing device which can automatically calculate a map by IFS(iterated function system) logic at a high speed for an input image in a complicated shape.

CONSTITUTION: The input image from an image input device 1 is transferred from an A/D converter 2 to a work memory 4 through an image data bus 9. A control processor 3 such as a microcomputer, a simulator 5 for a neural network which is composed of a dedicated LSI, etc., an auxiliary input/output device 6, and a D/A converter 7 are connected to the image data bus 9. An image output device 10 such as a monitor is connected to the D/A converter 7 and the respective devices are mutually connected through a system bus 8; and this fractal image compressing device reduces the input image by utilizing the energy function of the mutually coupled type neural network.