To reduce a required time until start of display based on decoded image data by conducting, immediately decoding processing without awaiting for the supply of an I picture of succeeding GOP at changeover of bit streams.

A demultiplexer 13 selects a compression stream based on an arbitrary image from plural received video image compression data, and a high speed MPEG decoder 14 decodes the coded stream by the demultiplexer 13 at a high speed. A buffer 15 always stores each stream not selected by one preceding GOP. In the case of switching video images, the buffer 15 supplies the compression stream of the newly selected video image or the like from the compression stream to the high speed MPEG decoder 14 at a high speed. When there are no more stored data in the buffer 15, the demultiplexer 13 supplies data to the high speed MPEG decoder 14 or the like directly, where the data are decoded. Since the data are immediately decoded without awaiting the supply of the I picture to be decoded, the time until the display start of the decoded video image is reduced.