The present inventors obtained, from a phage library of human antibodies, an anti-mouse NR 10 neutralizing antibody-expressing BM095 clone that shows a strong proliferation-suppressing activity in an IL-31-dependent Ba/F3 cell proliferation assay system. When this anti-mouse NR 10 neutralizing antibody was administered to NC/Nga mice, a model of atopic dermatitis which is a mouse model of chronic dermatitis that arises as a result of repeated applications of picryl chloride, a mouse model of rheumatoid arthritis, and a mouse model of osteoarthritis, a significant effect of symptom suppression was observed. This revealed that the anti-NR 10 neutralizing antibody is indeed effective as a therapeutic agent for inflammatory diseases. In addition, the present inventors successfully obtained an anti-human NR 10 neutralizing antibody, providing extremely useful therapeutic agents with practical clinical applications.