An image capturing apparatus comprises an image sensor that outputs a first added signal and a first average partial signal amplified by a first gain, and a second added signal and a second averaged partial signal amplified by a second gain, a processing unit that generates a third added signal by synthesizing the first and second added signals with a first ratio and a third averaged partial signal by synthesizing the first and second averaged partial signals with a second or third ratio, a determination unit that determines the first ratio based on the first or second added signal and determines the second ratio based on the first ratios, and changes the second ratio of a pixel group that includes a pixel corresponding to the saturated first or second added signal to the third ratio, which is not based on the first ratio.