An image forming apparatus includes: an image forming section that forms an image on a recording medium; a fixing section that includes a heat roller with a heater inside and fixes a toner image on the recording medium; a temperature detecting section for detecting the temperature of an end region of the heat roller in a direction of a rotary axis thereof; a control section that controls the operation of the heater based on the detected temperature; and a post-drive time calculating section that calculates a post-drive time for a post-drive of the fixing section after a successive image formation on recording media, depending upon the sizes of the recording media and through a subtraction using a correction factor set according to a condition of conveyance of the recording media. The control section causes the fixing section to perform the post-drive for the calculated post-drive time.