When shooting an image at a normal frame rate, and continuing to shoot the image by changing the frame rate to a high-speed frame rate, the image shooting apparatus of the present invention, before the frame rate is actually changed, causes the aperture to transit to a value which ensure that the amount of exposure before the change of the frame rate is ensured after the change, in correspondence with the exposure time that can be ensured during the high-speed shooting, and causes the exposure time to transit to the exposure time that can be ensured during the high-speed shooting, so that the frame rate is changed quickly and the image is reproduced smoothly when a portion corresponding to the frame rate change is reproduced.