To provide an anti-human BDCA-2 antibody which binds to human BDCA-2, and with which autoimmune diseases are prevented or treated by using human BDCA-2 to regulate the function of plasmacytoid dendritic cells. The inventors of the present invention examined anti-human BDCA-2 antibodies, and have provided an anti-human BDCA-2 antibody which includes: a heavy chain variable region comprising the amino acid sequence from amino acid number 1 to amino acid number 120 in SEQ ID NO: 2, and a light chain variable region comprising the amino acid sequence from amino acid number 1 to amino acid number 109 in SEQ ID NO: 4； a heavy chain variable region comprising the amino acid sequence from amino acid number 1 to amino acid number 120 in SEQ ID NO: 6, and a light chain variable region comprising the amino acid sequence from amino acid number 1 to amino acid number 108 in SEQ ID NO: 8； and a heavy chain variable region comprising the amino acid sequence from amino acid number 1 to amino acid number 122 in SEQ ID NO: 10, and a light chain variable region comprising the amino acid sequence from amino acid number 1 to amino acid number 108 in SEQ ID NO: 12.
