An image-capturing system includes: an image-capturing device that captures an image of a subject; and an illumination device that illuminates the subject. The image-capturing device includes a control unit that calculates a light quantity needed to illuminate the subject based upon at least, either an exposure time or an aperture value and image-capturing sensitivity. The illumination device includes a current-controlled light emission unit that emits light used to illuminate the subject and a light emission control unit that controls the light emission unit so as to emit light in the light quantity calculated by the control unit.