An image reading apparatus comprising: an automatic document feeding apparatus which conveying a document that has a part written by pigment that becomes colorless when heated and is loaded in a document tray to a sheet discharge location via a conveying path that passes through a prescribed reading out position; a reading section for obtaining an image information by reading out optically from the document which is conveyed by the automatic document feeding apparatus at the reading out position; a storage section for storing the image information obtained by reading the document in the reading section; and a heating unit for heating the document in a temperature of the pigment becomes colorless on a downstream side of the reading out position while the document passing through the conveying path.