To provide the X-ray image forming method by using a regular type silver halide photographic sensitive material having rapid processing aptitude.

At least one of silver halide emulsion layers satisfies the following conditions, and this silver halide photographic photosensitive material is imagewise exposed to X-rays by bringing a fluorescent sensitizing paper having an X-ray maximum emission spectrum in 350-500nm into contact with the silver halide emulsion layer side of this photosensitive material. 1: Silver halide grains are flat grains having an average aspect ratio of 2-15, and spectrally sensitized so as to have the maximum value in 350-500nm. 2: The outer most hydrophilic colloidal layer of this emulsion layer contains a matting agent having an average particle diameter of 3.0-7.0μm. 3: These silver halide grains have an average particle diameter of 1/15-1/5 of the average particle diameter of these matting agent. The above fluorescent sensitizing paper is essentially composed of an yttrium tantalate type of a barium halide type fluorescent material.