1. An image reading apparatus comprising: an image reading section which reads an image of a document to obtain image information; a first identification section to which the image information obtained from the image reading section is input, and which determines whether the image information is image information of a character area or other areas based on a first identification reference value; a second identification section which determines whether the image information determined as the character area is chromatic or achromatic based on a second identification reference value; an operation section for inputting and adjusting the first identification reference value and the second identification reference value; and a display control section which receives a first adjustment content of the first identification reference value and a second adjustment content of the second identification reference value from the operation section and which displays the first adjustment content and the second adjustment content on a same screen of a display.