To provide a copying device which produces single-sided to both-sided documents using only documents, dispenses with pre-counting required to count and sort the documents from the top since the documents are divided in advance from the bottom into odd-numbered documents and even-numbered documents, thereby lessening damage to the documents and increasing the speed.

The copying device includes a document placement tray and a control means. The control means selects odd-numbered documents from the bottom of the stack on the document placement tray and copies the contents of the even-numbered documents from the bottom of the stack onto the backsides of the odd-numbered documents from the bottom of the stack. If the number of the documents is odd, the last document is output as it is. If the number of the documents is even, all the copying sheets are ejected and inverted.