Abstract: A method for producing a monoclonal antibody and antigen-specific antibody-producing hybridomas using a single antigen-specific B lymphocyte is provided. The method for producing antigen-specific antibody-producing hybridomas comprises selecting a single B lymphocyte reacting specifically with a certain antigen, an “antigen-specific B lymphocyte”, culturing the antigen-specific B lymphocyte selected, and fusing the cultured antigen-specific B lymphocyte with myeloma cells to obtain the hybridomas. The monoclonal antibody is produced with thus obtained hybridomas.