PURPOSE: To simultaneously convert data inputted from a communicating means by a picture compressing and extending device, and transfer the data to the communicating means.

CONSTITUTION: Compressed code data inputted from the communicating means are transmitted to a MPM 14 by a CPU 16. The CPU 16 transmits a command to a CPU 11 by an inter-CPU communicating means so that the code data on an MPM 14 can be extended. The CPU 11 instructs extension to the compressing and extending means, and executes the control of a compressing and extending means 13. During that period of time the CPU 16 controls the transfer of the data to an SCS 117. This operation is repeated until data are ended, so that the extension processing and the data transfer can be simultaneously processed. When the extending request of the next compressed code data is issued, the transfer of image data and the extension of the compressed code data can be simultaneously processed.