PURPOSE: To obtain a copying machine which can calculate toner adhering rate (printing rate) at the time of copying, change the fixing temperature of a fixing device according to the printing rate, and substantially and fixedly keep fixing strength regardless of the printing rate.

CONSTITUTION: The constitution of the copying machine includes a scanning device 11 scanning the copying surface of an original paper, an image processing unit 9 calculating the printing rate of the original paper based on scanning result by means of the scanning device 11, the fixing device fixing toner on a transferring paper, and a central controlling unit 5 controlling the fixing temperature of the fixing device according to the printing rate calculated by the image processing unit 9.