A first direction determining unit determines, with respect to each of directions in image data corresponding to an image that contains text, a degree of certainty that the direction corresponds to a predetermined direction of the image to obtain a first direction with the highest degree of certainty and a second direction with the second-highest degree of certainty. When the first direction is opposite to the second direction, a second direction determining unit determines whether the predetermined direction corresponds to the first direction or the second direction based on a position of a text line extracted from the image data.