The present invention relates to an antibody that specifically binds to death receptor 5 (DR5) and has a function of killing cancer cells. Specifically, provided are an anti-DR5 antibody or antigen-binding fragment thereof, and a use of the antibody or antigen-binding fragment for preventing or treating cancer. The present invention is characterized in that the anti-DR5 antibody or antigen-binding fragment thereof is improved in terms of affinity to DR5, stability, and an effect of killing cancer cells.
