A high-sensitive phase imaging is achieved using a grating section without upsizing the imaging device or narrowing the period of the gratings. A radiation source generates radiation on a radiation path toward the grating section. The grating section comprises a G1 grating and a refraction-enhancing grating. The G1 grating has a G1 periodic structure that forms radiation converging points where an intensity of the radiation is increased between the G1 grating and a detector. The refraction-enhancing grating is located at the position of the radiation converging points and has enhancement planes and that increase the refraction angle of the radiation. The detector detects the radiation that has passed through the grating section.