To calculate an appropriate white balance gain even when a white balance gain at the time of flash emission is unknown.

The present invention is provided with a multi AWB processing unit 106 for calculating an exposure difference value from a difference in exposure control value between a first image when flash is not emitted and a second image when flash is emitted; calculating a first flash mixture ratio in units of a prescribed block by comparing signal values of the first and the second images multiplied by the exposure difference value; selecting a block area where the first flash mixture ratio fits in between a maximum value of the first flash mixture ratio and a prescribed threshold value; calculating a color balance of the selected area of the second image; calculating a second flash mixture ratio by multiplying the first flash mixture ratio of the whole block by a coefficient defining the maximum value as 1; and calculating a white balance gain in block units on the basis of the second flash mixture ratio, a color balance of the selected area of the second image, and a color balance of a fixed light.