It is intended to identify a substance inhibiting an odor caused by 2,5-dimethyl-4-hydroxy-3(2H)-furanone. The present invention provides a method for searching for an inhibitor of an odor caused by 2,5-dimethyl-4-hydroxy-3(2H)-furanone, comprising: adding a test substance and 2,5-dimethyl-4-hydroxy-3(2H)-furanone to an olfactory receptor OR5K1 or a polypeptide having at least 80% amino acid sequence identity thereto; measuring the response of the olfactory receptor or the polypeptide to 2,5-dimethyl-4-hydroxy-3(2H)-furanone; and identifying a test substance inhibiting the response of the olfactory receptor or the polypeptide, on the basis of the measured response.