The present invention relates to an antibody which has a therapeutic effect on cancer, an autoimmune disease, or an inflammatory disease. That is, the present invention relates to an antibody which exhibits a cytotoxic activity against death domain-containing receptor-expressing cells through apoptosis. [Object] An object of the invention is to provide a pharmaceutical having a therapeutic effect on cancer. [Means for Resolution] A novel anti-DR5 antibody capable of inducing apoptosis in cells has more potent cytotoxic activity than currently available anti-DR5 antibodies.