PROBLEM TO BE SOLVED: To provide a GLP-1 secretion promoter, an insulin secretion promoter, a blood glucose level reducing agent, a diabetes preventive agent, a diabetes therapeutic agent, and a lipid metabolism improver.SOLUTION: The present invention relates to a GLP-1 secretion promoter, an insulin secretion promoter, a blood glucose level reducing agent, a diabetes preventive agent, a diabetes therapeutic agent, and a lipid metabolism improver, comprising a compound represented by the following formula (I) or a salt thereof.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2016,JPO&INPIT