An image forming apparatus is operable in a first mode in which a control unit is in a rest state and a second mode in which electric power is supplied to the control unit. The image forming apparatuschanges the mode of the operation to the second mode of the operation in response to detection of putting of the sheet on the manual feeding tray during execution of the operation in the first mode with the pressing mechanism being in the second position, and then in response to receipt of input of a predetermined instruction about an image forming operation by a receiving portion in the second mode, the control unit controls the moving mechanism so that the pressing mechanism moves from the low pressure position to a nip-forming position.