The present invention relates to an anticancer composition comprising an antitumor agent as well as a substance having inhibitory effects on the activity or expression of L1CAM more particularly, to an anticancer composition, which comprises an anti-L1CAM antibody specific to L1CAM, serving as a substance for inhibiting the activity of L1CAM an oligonucleotide inhibiting the generation of L1CAM, serving as a substance for inhibiting the expression of L1CAM and a substance selected from cisplatin, gemcitabine, 5-fluorouracil and taxol, serving as an antitumor agent. The composition according to the present invention has the benefit of the combined use of a substance having inhibitory effects on the activity or an expression of L1CAM and an antitumor agent concurrently, separately or sequentially so that it demonstrates stronger and more significant pharmaceutical effects than the exclusive use of those substances on inhibiting proliferation and inducing apoptosis in cancer cells, thereby making it very useful for cancer treatment.
