An image processing apparatus includes: a platen; a document cover mounted to be opened/closed on the platen; a document reader provided in relation to the platen, for reading an image of a document placed on the platen; an opening/closing detector provided in relation to the platen and the document cover, for detecting opening/closing of the document cover; an operation panel designating how the read document is to be arranged at the time of output; a document output device arranging and outputting the document images read by the document reader, in accordance with the arrangement designated by the operation panel; and a reading operation controller inhibiting document reading, when a specific arrangement of document images is designated by the operation panel and opening/closing operation of the document cover is not detected by the opening/closing detector.