A pointer comparing unit determines whether a value of a writing pointer is identical to a value of a reading pointer. When it is determined that the value of the writing pointer is different from the value of the reading pointer, an inter-memory transfer unit reads data stored in a location where a data transfer apparatus reads transmission data from a transmission ring buffer, transfers the data to a reception memory, and writes the data in a location designated by the reading pointer of a reception ring buffer. When the inter-memory transfer unit completes writing of the data in the reception ring buffer, a reading-pointer updating unit updates the reading pointer.