Provided are a pharmaceutical composition for suppressing a resistance to a targeted anticancer drug, which at least one selected from the group consisting of an integrin β3 neutralizing antibody, integrin β3 siRNA, Src inhibitor, and Src siRNA as an active ingredient, and an anticancer supplement. The pharmaceutical composition may increase an anticancer therapeutic effect when administered in combination with a conventional targeted anticancer drug. In addition, the pharmaceutical composition is expected to be used in development of an integrin β3-targeted targeted anticancer drug.
