An image capturing apparatus that has an image capturing device including polarization elements and sets a proper frame rate according to a situation when acquiring a video using polarization information. The image capturing device an image capturing device including polarization pixels that detect polarization information of a plurality of different directions. The polarization information of the polarization pixels is determined by performing first polarization calculation or second polarization calculation which is smaller in calculation load than the first polarization calculation, on video signals output from the polarization pixels. A polarization-processed image is generated by using the polarization information. The first polarization calculation and the second polarization calculation are switched according to a predetermined timing, a mode, or a result of detecting a predetermined state.