A developing processing method and an image forming method are described, which comprise the steps of (a) exposing a silver halide photographic material comprising a support having thereon at least one light-sensitive silver halide emulsion layer; and (b) developing the exposed silver halide photographic material with a developer containing a developing agent, containing substantially no dihydroxybenzene developing agent, containing an auxiliary developing agent exhibiting a superadditive property, containing a quaternary onium salt compound, and having a pH value of from 9.5 to 11.5, or a developer containing a developing agent, containing substantially no dihydroxybenzene developing agent, and having a pH value of from 10 or less.