At least one of a nucleus forming process, a nucleus growing process, a chemical sensitizing process, and a spectral sensitizing process for producing a silver halide photographic emulsion is performed by using a microreactor. A minute region of the microreactor is used to precisely perform a reaction of nucleus formation. A condition under which host grains are allowed to react with newly supplied silver halide nuclei is made uniform to cause uniform crystal growth. A predetermined quantity of molecules for chemical sensitization is doped in a crystal lattice of a nucleus of silver halide to effect a sensitizing process. Alternatively, a spectral sensitizing process in which a single molecular layer of a spectral sensitizer is uniformly adsorbed on a silver halide nucleus grain surface is securely carried out.