The present invention provides a monoclonal antibody that recognizes the V3 loop of the envelope glycoprotein gp120 of AIDS virus, which is any one selected from the following antibodies:(a) an antibody having the amino acid sequence shown in SEQ ID NO: 1 as the amino acid sequence of a H chain variable region (VH), and having the amino acid sequence shown in SEQ ID NO: 2 as the amino acid sequence of a L chain variable region (VL) and(b) an antibody having the amino acid sequence shown in SEQ ID NO: 3 as the amino acid sequence of a H chain variable region (VH), and having the amino acid sequence shown in SEQ ID NO: 4 as the amino acid sequence of a L chain variable region (VL).
