Abstract: A compound represented by the formula [1]: wherein ring A and ring B each represent an optionally substituted benzene ring; ring C represents an optionally further substituted aromatic ring; R1 represents a lower alkyl group optionally substituted with an optionally substituted hydroxyl group; X1a represents a bond or optionally substituted lower alkylene; X1b represents a bond or optionally substituted lower alkylene; x2 represents a bond, —O— or —S—; X3 represents a bond or an optionally substituted divalent hydrocarbon group; Y represents an optionally esterified or amidated carboxyl group, or a salt thereof. The compound of the formula [I] is safer and has more potent lipid lowering activity such as squalene synthase inhibitory activity (cholesterol lowering activity) and triglyceride lowering activity, and thus it is a compound useful as an agent for preventing or treating hyperlipemia.