Injections for treating and preventing diseases classified as any of grade 1 to 3 according to the ICRS classification of osteoarthritis, diseases classified as any of grade 1 to 3 according to the Kellgren-Lawrence classification of osteoarthritis or diseases classified as any of grade 1 to 3 according to the Outerbridge classification of osteoarthritis contain anti-Fas IgM antibody as an active ingredient and a pharmaceutically acceptable carrier to alleviate osteoarthritis symptoms by inhibiting the production of cartilage matrix degrading enzymes and by increasing the production of cartilage matrix.