A binarizing unit binarizes a multilevel image. A region specifying unit A specifies the position of a character region in the binary image, and determines whether or not the specified character region is an inverted character region. A region specifying unit B specifies the position of a unit character region. A reducing unit reduces the multilevel image. A representative color extracting unit extracts the representative color of a unit character region on the basis of region type information indicating whether or not a character region is an inverted character region, position information of a unit character region, and a reduced multilevel image. A character region padding unit pads a character region of a reduced multilevel image with its neighboring color on the basis of position information of the character region. A JPEG compressing unit compresses a padded reduced multilevel image. An MMR compressing unit compresses a partial binary image corresponding to a character region. Compressed data containing position information, the compressed code created by each compressing unit, and the representative color information of a unit character region is output.