This X-ray phase difference imaging system (100) includes an X-ray source (1), a plurality of gratings, a detector (4), and an image processor (6), in which the image processor (6) is configured to correct an artifact of a second phase contrast image (10b) that is reconstructed by using a first X-ray image (9a) and a third X-ray image (9c), on the basis of a first phase contrast image (10a) that is reconstructed by using the first X-ray image (9a) and a second X-ray image (9b).