Metabolic syndrome is a combination of hypercholesterolemia, hypertriglyceridemia, impaired glucose tolerance, hypertension and obesity, even though the individual symptoms are not serious. Metabolic syndrome causes a circulatory system diseases which is one of the main causes of death. There are provided a composition having an ameliorating and preventing effect on metabolic syndrome which contains astaxanthin-containing extract as an effective ingredient, and a beverage, a food or a pharmaceutical preparation for metabolic syndrome which contains astaxanthin-containing extract as an effective ingredient. Astaxanthin-containing extract is also effective for ameliorating and preventing hypertension, hyperlipemia, diabetes or obesity which is a symptom of metabolic syndrome.