Provided is an image processing apparatus sequentially performing image processing on multiple pieces of band data composing image data. The image processing apparatus includes a RAM and a JPEG encoding circuit. The RAM has a buffer area of a fixed length. The JPEG encoding circuit sequentially performs variable-length encoding on multiple pieces of band data, sequentially writes the band data subjected to the encoding from the beginning of the buffer area, and writes subsequent band data subjected to the encoding from the beginning of the buffer area if the end of the band data subjected to the encoding is positioned in a boundary area having a certain length including an ending part of the buffer area.