An image forming apparatus is capable of reducing the time when it is unable to perform image formation due to a temperature change of an image bearing member. The apparatus includes a rotatable image bearing member; an electrostatic image forming device for continuously forming electrostatic images on the image bearing member based on forming image amount information; a toner image forming device for developing the electrostatic image and forming a toner image; a primary transferring device for transferring the toner image on the image bearing member to a rotatable intermediate transferring member; a simultaneously transferring and fixing device for transferring the toner image on the intermediate transferring member to a recording material and heating and fixing it; a detector detects a temperature of the image bearing member; and a starting device starts the electrostatic image forming device based on a detection result and the forming image amount information.