An image forming apparatus includes an image reading unit, an image forming unit, an acceptance unit, a paper transporting unit, a mode selecting unit, and a control unit. The image reading unit includes a document transporting device, a loaded-document detecting unit, a document table, a document holder, and a placed-document detecting unit. The mode selection unit can select a first mode in which paper is transported at the start of image reading operation and a second mode in which paper is transported after the image reading operation. If the loaded-document detecting unit detects that a document has not been loaded in a loading position and the placed-document detecting unit detects that a document has not been placed on the document table, the control unit controls the mode selection unit to select the second mode and controls the image reading unit to read an image on the document table.