To enable color shift correction arising in a color composite image any time (at an arbitrary timing) and under conditions suitable for the apparatus state of that time.

The data obtained from a table of EEPROM saved by associating the various amounts of the previously determined color shifts with the temperature when the amounts of the shifts are determined is used without performing detection of the patterns for correction and color shift calculation at the time of the color shift correction. In the color shift correction processing, the present temperature is detected during image formation (S101), and the amount of the shift is acquired (S102) by referencing the various amounts of the color shifts saved according to the detected temperatures and the control conditions are corrected based on the acquired amount of the shift and the appropriate image output is obtained.