Generally, antitumor drugs have strong toxicity and result in damage in normal cells. Previously, lectin has been reported as a tumor cell specific binding protein and tannin as an antitumor substance. In this study, we investigated antitumor activity of lectin-conjugated ellagitannin and used praecoxin A as an ellagitannin source. We injected mouse melanoma cell, B16-F10, on right the femoral region of C57BL/6 mouse. After 10 hours later, first treatment with praecoxin A, lectin-praecoxin A mixiture and lectin-conjugated praecoxin A was carried and followed by injection i.m. every 48 hours. Praecoxin A extended the life of mice up to 14.8% in comparison with the negative control group at 5 mg/kg dose. The life extending ratio of Lectin-praecoxin A mixture was 26.1% at 5 mg/kg dose, and the life extending ratio of lectin-conjugated praecoxin A was 28.7% at 5 mg/kg dose. On the basis of these findings, we suggest that antitumor activities of lectin-praecoxin A mixiture and lectin-conjugated praecoxin A on survival are better than that of praecoxin A.