[en] The conventional x-ray imaging for soft tissue often produced some adverse effects because of contrast medium and high-dose radiation. This report outlines the recently developed a very sensitive x-ray imaging method called as refraction contrast method or x-ray Schlieren method, which allows to detect density difference and irregularity in the soft tissue. In the apparatus (SPring-8 BL47XU), a light emitted from undulator was monochromatized by two-crystal x-ray spectroscope and x-ray passed through a sample was caught by imaging detector equipped with a combination of relay lens and CCD. When a glass capillary (outer diameter: 660 μm, inner diameter: 220 μm) was used as a measuring sample, it was confirmed that the image through geometrical refraction was obtained. When x-ray images of a dragonfly wing obtained by the Schlieren method (sample-detector distance: 5 m) and the conventional contact method were compared, it was demonstrated that reticulate structure of the wing was clearly observed by the former method but not at all by the latter one. At present, the study on efficacy of the refraction contrast imaging is under way using rodents. (M.N.)