To remove or ameliorate the stripes on an image generated by exposure density unevenness and more particularly the multiexposure history difference of light source points as both ends of an exposure head in an image forming method of a scanning exposure type using plural pieces of the exposure light sources of ≤10-3 seconds in exposure time.

This image forming method is a method of exposing a photosensitive material having at least a photosensitive silver halide emulsion and a binder on a base by using an exposure head having the plural beam light sources which correspond to the exposure points and emit respectively the same wavelength light. The exposure heads are constituted by arraying M-pieces of the beam light sources at prescribed intervals in a sub-scanning direction orthogonal with a main scanning direction where the exposure heads themselves are moved. The photosensitive material is moved by (the length in the arraying direction of the exposure heads/N (N≥2) each in the sub- scanning direction and is subjected to overlap exposure of N times at ≤10-3 second per exposure time, by which m×N pixels are formed per exposure head at each of M pieces of the exposure point. At the time of image formation, the amount of the Ir to be added in the silver halide emulsion of the photosensitive material is specified to 10-7 to 10-16 mol per mol of the silver halide.