To enable data disclosed in a public region on the memory of an STB1 to be acquired and processed without causing interruption of the data processing due to the data acquisition.

An STB2 independently execute: processing for reading a necessary program or data from an internal memory according to processing and executing the program or the data; and processing for reading, from the public region of an STB1 beforehand, the program or data predicted to be processed next to the program or data read from a main and for causing the main to store the program or data.