PURPOSE: To provide an image processing method, image processor and X-ray radiographing device with which any afterimage is not generated in a display image even when an object moves in the case of using a recursive filter.

CONSTITUTION: This device is provided with an X-ray detecting means 6 for detecting an X-ray emitted from an X-ray irradiation means 1 and transmitted through the object 2, image data forming means 10 for forming the input image data of the object 2 based on the output signal of the X-ray detecting means 6, image storage means 12 for storing the output image data, recursive filtering means 11 for finding the output image data of a current frame from the input image data formed by the image data forming means 10 and output image data read out of the image storage means 12, moving amount calculating means 14 for finding the moving amount of the object, and read out control means 15 for controlling the reading out position of the output image data from the image storage means 12 based on the moving amount of the object found by the moving amount calculating means 14.