This is to provide a continuous arycyclic compound having a DGAT1 inhibitory activity, and useful for prophylaxis and/or treatment of obesity or hyperlipidemia caused by obesity, hypertriglyceridemia, lipid metabolism disorder, fatty liver, hypertension, arteriosclerosis, diabetes, etc., as well as to provide a DGAT1 inhibitor comprising the continuous arycyclic compound or a pharmaceutically acceptable salt thereof as an effective ingredient. Disclosed is the continuous arycyclic compound is represented by the formula: wherein the substituents in the formula are the same as defined in the specification, or a pharmaceutically acceptable salt thereof.