To provide a treating method of a black-and-white silver halide photographic sensitive material, especially a platemaking photosensitive material, by which changes in the photographic performance due to residual colors or scratches on the surface can be avoided after the photosensitive material is treated even when the photosensitive material is subjected to fast treatment in a largely reduced treating time while a replenishes amt. is largely decreased, and by which the obtd. image has excellent preservable property.

After a black-and-white silver halide photographic sensitive material is treated with a fixing liquid, the material is treated with washing water or rising liquid. In this method, a film essentially comprising syndyotactic polystyrene is used as the supporting body of the photosensitive material. The replenishing amt. of the fixing liquid is ≤300 ml/m2. The washing process or rising process is carried out in a multistage counter flow method with ≤2 l/m2 replenishing amt. of the washing water or rinsing liquid.