To obtain the subject new peptide for identifying a ligand of a biological active factor or as an inhibitor for cancer cell metastasis, comprising a peptide to be specifically reacted with an antibody against a glycolipid sugar chain and to inhibit a cancer cell from bonding to and metastasizing to a target cell.

This new glycolipid sugar chain replica peptide is specifically reacted with an antibody of a sugar chain of glycolipid and inhibits a cancer cell from bonding to and/or metastasizing to a target cell. The peptide is specifically reacted with an antibody against one GD1 α of a ganglioside which is a sialic acid-containing sphingoglycolipid. The peptide is effective as a medicine composition for identifying a ligand for mediating biological activity to be a target and suppressing cancer metastasis by inhibiting a cancer metastasis cell from bonding to and/or metastasizing to a target cell. The peptide is obtained by selecting a phage containing a peptide to be reacted with an antibody against glycolipid from a phage display peptide library of fibrous phage of Escherichia coli.