PROBLEM TO BE SOLVED: To remove a grid shade sufficiently without deteriorating information useful for diagnosis from an original image including a grid shadow difficult to be removed.SOLUTION: An X-ray image photographing apparatus includes: a filter processing part 12c which uses a smoothing filter having a square kernel longer in the long axis direction of a grid panel shade with respect to a wavelet conversion coefficient selected from among a group of wavelet conversion coefficients to perform filter processing in accordance with a long axis direction of the grid plate shade on an original image attributed to the grid panel a grid on the front surface of a detector has and generates a wavelet conversion coefficient after the filter processing an inverse wavelet conversion processing part 12d which uses only the wavelet conversion coefficient filter processed and generates an extraction image from which a grid panel shade is extracted a difference processing part 12e for generating a difference image by performing difference processing between the original image and the extraction image to generate a difference image and a display processing part 125 for performing display processing of the difference image.
