1. An image-reading device comprising: a reading unit that reads an original document as image data; a displaying unit that displays the image data read by the reading unit; a recognition target region setting unit that sets a recognition target region within the displayed image data to recognize characters; a character recognizing unit that performs character recognition in the recognition target region, the character recognizing unit including a page recognizing unit recognizing a page number provided in the recognition target region; and a reading error determining unit determining whether or not a page reading error has occurred based on recognition results by the page recognizing unit.