A novel therapeutic agent for hyperlipidemia, which is an ester compound represented by the formula (1″) (wherein R1 and R2 are each hydrogen atom or optionally substituted aryl, etc.; X is —COO— or —CON(R10)—; R3 and R4 are each hydrogen atom, C1-C6alkyl or C1-C6alkoxy, etc.; R5, R6 and R7 are each hydrogen atom, C1-C6 alkyl or C1-C6 alkoxy, etc.; R8 and R9 are each independently hydrogen atom, C1-C6alkyl, —CON(R18)(R19) or —COO(R20), etc.; ring A, ring B and ring C are each independently aryl or heterocycle residue, etc.; Alk1 and Alk2 are each independently alkanediyl, etc.; l and m are each an integer of 0 or 1 to 3) or a prodrug thereof, or a pharmaceutically acceptable salt of either. The therapeutic agent selectively inhibits MTP in the small intestine, thus causes no such side effect as a fatty liver.