To provide an image-capturing system capable of maintaining high analysis accuracy while reducing the amount of data related to image acquisition with a simple method. In order to achieve the object, the image-capturing system includes an image-capturing device configured to acquire image data of a subject, and an image-capturing control device configured to control image acquisition by the image-capturing device. The image-capturing control device includes a difference extraction means configured to extract difference data on the basis of any two image data items acquired by the image-capturing device, a change amount extraction means configured to extract change amount data on the basis of any two difference data items extracted by the difference extraction means, and a condition change means configured to change an image acquisition condition in the image-capturing device on the basis of the change amount data extracted by the change amount extraction means.