An image forming apparatus which can prevent a temperature increase at predetermined locations of a fixing unit and also realize the fastest printing with respect to each continuous printing number. The image forming apparatus includes a fixing unit that fixes an image supported on a recording material passing through the nip section, and a conveying unit that conveys the recording material to the fixing unit at a throughput representing the number of recording materials conveyed to the fixing unit per unit time. The printing number is set in continuous printing on the recording materials, and the size of the recording material is acquired. Nearly the highest throughput is set as the predetermined throughput based on the set printing numbers and the acquired size of the recording material so that the continuous printing is completed before a temperature at predetermined locations in the fixing unit reaches an upper limit.