An image forming apparatus is provided with an image reading unit for reading the image information of a document and an image forming unit for performing a specified image forming process based on this image information. The image reading unit includes a contact glass on which a document to have image information read therefrom is to be placed, an image reading unit main body on which the contact glass is mounted, a document pressing member openable and closable to press a document placed on the contact glass, and an optical member for optically scanning a document surface of the document placed on the contact glass to read as a document image. The image reading unit main body includes a top panel formed with an opening covered by the contact glass and the outer surface of the top panel is in a dark color.