1. A white balance processing apparatus comprising: white balance processing means for effecting white balance processing on a taken image based on a set white balance value; non-volatile storage means for storing white balance values set for the taken image obtained in past image taking and employed in said white balance processing; custom value setting means for setting a white balance value employed in the past, stored in the storage means as a custom white balance value for the taken image by a new picture taking; detected value setting means for detecting and setting a white balance value to be set to said white balance processing means from the taken image; correction means for correcting said detected white balance value; and corrected detected value setting means for setting said corrected detected white balance value to said white balance processing means; wherein said storage means additionally stores said corrected detected white balance value set and employed at said white balance processing means as a white balance value employed in the past.