Data which has been decoded by a decoding portion 101 are compressed by a compressing portion 102 and stored in a prediction/display frame memory portion 103. From the data stored in the prediction/display frame memory portion 103, any data required for decoding other frames in the decoding portion 101 are decompressed through a decompressing A portion 104 and supplied to the decoding portion 101. Alternatively, data to be displayed is read from the prediction/display frame memory portion 103, decompressed at a decompressing B portion 105 and supplied to a display apparatus. Writing to and reading from the above-mentioned prediction/display frame memory portion 103 is controlled by an address controlling portion 106. Since compressed data are stored in the prediction/display frame memory portion 103, the memory capacity can be decreased.