PURPOSE: To execute the processing corresponding to the number of frames of accumulated data at a high speed and easily by detecting a fact that there is a difference of one frame or above in count outputs of an input signal and an output signal.

CONSTITUTION: The hardware queue is provided with a flag detecting circuit 34 for detecting a closing flag added to the tail of data, sending out an input frame count signal 38 at the time when the data is an input signal, and sending out an output frame count signal 39 at the time when the data is an output signal. Also, this hardware queue is provided with an input frame counter 35 for counting the input frame count signal 38, an output frame counter 36 for counting the output frame count signal 39, and a comparator 37 for sending out a queue output ready signal 40 and a queue status signal 41 for showing the number of frames of a difference at the time when there is a difference of one frame or above. In such a way, whether the data accumulation to a hardware queue can be executed or not can be decided immediately, and also, what frame the accumulation data to be fetched by a queue status signal is can be decided.