PROBLEM TO BE SOLVED: To obtain an anti-integrin &alpha；3 antibody composite capable of inhibiting proliferation of tumor cells, for example, by introducing an antitumor agent, etc., into tumor cells by linking an integrin &alpha；3 antibody, etc., with a chemotherapeutic agent. SOLUTION: This anti-integrin &alpha；3 antibody composite is obtained by linking an anti-integrin &alpha；3 antibody (for example, monoclonal antibody) or its antigen- bondable fragment with chemotherapeutic agents, substances which have an antitumor effect, for example, antitumor agents, cytokines and enzymes except toxins, by means of their own lining group, a linker, intermediate supporter or combination of them. In this composite, the anti-integrin &alpha；3 antibody is internalized into cells that manifest integrin &alpha；3, and at this time, the chemotherapeutic agents linked with the antibody are introduced into the cells, thereby developing chemotherapeutic effects.
