An image processing apparatus comprising: a scanner configured to acquire a read image of an original document; a memory configured to store the read image of the original document that is acquired by the scanner; and a processor configured to: detect in the read image of the original document which is stored in the memory one or more chromatic color regions including a region that is highlighted with a chromatic color and a circled region including a region circled by the chromatic color, wherein the processor is further configured to extract a contour line (r1, r2) of a chromatic color region in the read image of the original document, determine that the chromatic color region is a mark indicating the highlighted region if a ratio of white pixels surrounded by the contour line over the total number of pixels included in the contour line is less than a threshold value, and determine that the chromatic color region is a mark indicating the circled region if the ratio of the white pixels surrounded by the contour line over the total number of pixels included in the contour line is greater than or equal to the threshold value, classify the highlighted region as a region for first processing, and classify the circled region as a region for second processing. a scanner configured to acquire a read image of an original document; a memory configured to store the read image of the original document that is acquired by the scanner; and a processor configured to: detect in the read image of the original document which is stored in the memory one or more chromatic color regions including a region that is highlighted with a chromatic color and a circled region including a region circled by the chromatic color, wherein the processor is further configured to extract a contour line (r1, r2) of a chromatic color region in the read image of the original document, determine that the chromatic color region is a mark indicating the highlighted region if a ratio of white pixels surrounded by the contour line over the total number of pixels included in the contour line is less than a threshold value, and determine that the chromatic color region is a mark indicating the circled region if the ratio of the white pixels surrounded by the contour line over the total number of pixels included in the contour line is greater than or equal to the threshold value, classify the highlighted region as a region for first processing, and classify the circled region as a region for second processing. detect in the read image of the original document which is stored in the memory one or more chromatic color regions including a region that is highlighted with a chromatic color and a circled region including a region circled by the chromatic color, wherein the processor is further configured to extract a contour line (r1, r2) of a chromatic color region in the read image of the original document, determine that the chromatic color region is a mark indicating the highlighted region if a ratio of white pixels surrounded by the contour line over the total number of pixels included in the contour line is less than a threshold value, and determine that the chromatic color region is a mark indicating the circled region if the ratio of the white pixels surrounded by the contour line over the total number of pixels included in the contour line is greater than or equal to the threshold value, classify the highlighted region as a region for first processing, and classify the circled region as a region for second processing.