The present invention relates to a method of enhancing the salty taste of a food or beverage containing salt which comprises adding an acidic peptide or a peptide obtained by subjecting a protein to hydrolysis and deamidation to the food or beverage, a salty taste enhancer comprising the peptide as an active ingredient, a salty taste seasoning agent comprising the peptide and salt, and a food or beverage comprising the salty taste enhancer or the salty taste seasoning agent.