A picture start code detecting section 131 detects the input timing of the leading data of a picture from TS packets inputted to a buffer 11. A counter 132 outputs a timing signal at the time when the leading data of the picture has been inputted 30 times, thereby detecting the input timing of data of one second. A counter 133 counts the data amount of TS packets inputted to the buffer 11 during the period of time from the reception of a timing signal from the counter 132 to the next reception. The count value is read via a DFF 134 and inputted to a read control section 135. The read control section 135 sets the input value from the DFF 134 as the reading speed of TS packets from the buffer 11.