An image forming apparatus includes: an image forming unit configured to form a toner image on a paper sheet; a fixing unit configured to fix the toner image onto the paper sheet; a fixing temperature detecting unit configured to detect a fixing temperature in the fixing unit; and a control unit configured to allow a fixing operation in the fixing unit only after the fixing temperature is adjusted to be within a predetermined allowable fixing temperature range, when the fixing temperature is outside the allowable fixing temperature range, wherein the control unit sets the allowable fixing temperature range in accordance with fixing properties required in an output of a pattern image for adjustment in an adjustment mode in which various kinds of adjustments related to image formation can be performed based on an output of the pattern image for adjustment.