An image forming apparatus, including a mechanism configured to switch an intermediate transfer member between a first state in which the intermediate transfer member is in contact with a first photosensitive drum for a color toner image and a second photosensitive drum for a black toner image in a full-color mode and a second state in which the intermediate transfer member is separated from the first photosensitive drum and in contact with the second photosensitive drum in a monochrome mode; and a control portion configured to control the mechanism according to a set color mode in response to a user operation from which a start of the image formation is predicted, without an instruction of image formation and thereafter control the mechanism according to a changed color mode if the set color mode is changed by a setting of the color mode before receiving the instruction of the image formation.