Peptide which is obtained by treating fish meat such as sardine with an alkaline protease is adsorbed with a peptide-adsorbing resin (such as ODS resin) and eluted with 10 aqueous ethanol to obtain a peptide (Y-2 fraction). The resulting novel peptide has an excellent hypotensive action and can be used as a nutrient and a specific health food and, in addition, it can be advantageously used as a hypotensive agent.