An image forming apparatus includes: a fixing device: having a heating member, a rotating member, and a temperature sensor; a sheet feeding unit; and a control device configured to perform a sheet feed control: in which the feeding timing is set to a first timing if the temperature gradient of the heating member for a predetermined period is larger than a first threshold value; and in which the feeding timing is set to a second timing later than the first timing if the temperature gradient of the heating member for the predetermined period is equal to or less than the first threshold value, and wherein, in the sheet feed control, the control device changes the first threshold value to a smaller value as the temperature of the heating member at the print-instruction receiving time increase.