The present invention provides an apparatus capable of X-ray imaging utilizing phase of X-rays. An X-ray imaging apparatus equipped with first and second diffraction gratings and an X-ray image detector are described. The first diffraction grating generates a Talbot effect and a second diffraction grating diffracts X-rays diffracted by the first diffraction grating. An image detector is provided to detect the X-rays diffracted by the second diffraction grating. In this manner, image contrasts caused by changes in phase of X-rays due to a subject arranged in front of the first diffraction grating or between the first diffraction grating and the second diffraction grating can be achieved.