The present invention provides an anti-cancer agent comprising anti-glypican 3 antibody wherein the anti-cancer agent is administered after a cancer treatment, Preferably, after a cancer treatment is after a treatment for liver cancer, and the treatment for liver cancer is in particular a resection of liver cancer cells. The anti-cancer agent according to the present invention is preferably administered if glypican 3 is expressed in the resected liver cancer cells. The anti-glypican 3 antibody is preferably a monoclonal antibody. The anti-cancer agent according to the present invention is useful for preventing cancer and for preventing the recurrence of cancer.
