To precisely position multiple radiation pictures obtained by a phase contrast radiographing method.

An X-ray 12 transmitting through an object 21 and positioning markers 22 and 23 is emitted on a detection panel 31, while moving the detection panel 31 to obtain picture data Sn expressing X-ray pictures of the object in multiple radiographing positions. A positioning part 40 detects central positions of multiple diffraction fringes appearing on the marker pictures, finds a mean value of the multiple central positions, and sets it as the central position of the marker pictures. The central positions of the marker pictures of the multiple data are found, the X-ray pictures expressed by the multiple picture data Sn are positioned based on the central positions, and an arithmetic part 50 obtains picture data S1 expressing the phase contrast picture.