A color image forming apparatus having a plural-color image print mode for successively forming images of plural colors, and a single-color image print mode for forming an image of a single color, is capable of forming, in the plural-color image print mode, a frame of single-color image, and thereafter superimposing and forming an image of the next color on the single-color image. The apparatus includes a fixing apparatus for fixing an image on a recording medium on which an image of plural colors or a single color has been formed, and a temperature controlling portion for controlling the temperature of the fixing apparatus so as to become a target temperature. The fixing apparatus has a heating member and a pressure member and transports the recording medium to a nip part constituted by the heating member and the pressure member. The temperature controlling portion, when continuous printing of plural sheets is to be effected, changes over the target temperature of the heating member when a predetermined number of sheets have been printed, and also changes the predetermined number of sheets for which the target temperature should be changed over, during single-color image printing and during plural-color image printing.