An object of the present invention is to provide an ameliorating agent for improving metabolic syndrome. The inventors focused on the efficacy of MUFA, which is richly contained in saury oil, on physiological actions. As a result of repeated research, the inventors discovered that C20:1 and C22:1 free fatty acids have an ameliorative effect on metabolic syndrome, and achieved the present invention. The present invention provides a metabolic syndrome ameliorating agent comprising a MUFA having 22 carbons. In addition, the present invention provides a metabolic syndrome ameliorating agent comprising a MUFA having 22 carbons and a MUFA having 20 carbons. Furthermore, the present invention provides a metabolic syndrome ameliorating agent comprising a fish oil including a MUFA having 22 carbons and a MUFA having 20 carbons.
