A bus switch is connected among an input buffer memory, a data memory, and an encoding unit, to select between a first bus connection of the input buffer memory and the data memory and a second bus connection of the data memory and the encoding unit. A data transfer control unit controls the bus switch to select the first bus connection in response to a data request signal from the encoding unit, controls the process of reading from the input buffer memory and the process of writing into the data memory, controls the bus switch to select the second bus connection upon completion of the transfer of one unit of image data, and sends a transfer completion signal in order of causing the encoding unit to start performing encoding processing. This makes it possible to transfer image data from the input buffer memory to the data memory at high speed.