PROBLEM TO BE SOLVED: To provide a novel peptide having dipeptidyl peptidase-IV inhibitory activity, and application thereof.SOLUTION: A peptide made up of any of the following (a) to (c) amino acid sequences, having an application as a blood sugar level elevation inhibitor, an anti-diabetic agent, a vascular endothelial function improver, a vascular endothelial disorder inhibitor or a food and drink. (a) Met-Gln-Gln-Met, (b)Leu-Arg-Gln-Gly-Asp, (c)Leu-His-Gln-Lys.SELECTED DRAWING: None