A compound represented by the following general formula (I): [wherein R1 and R2 represent an alkyl group, X represents —S—, —O— or —NH—, Y represents C or N, R3 represents hydrogen atom or a C1-10 alkyl group, Z represents —CO—N(R5)— (R5 represents hydrogen atom or a C1-6 alkyl group) or —C(R6)═C(R7)—CO—NH— (R6 and R7 represent hydrogen atom or a C1-6 alkyl group), Ar represents an aryldiyl group or a heteroaryldiyl group, and R4 represents —COOH, —OCH2—COOH, —CH2—COOH, or —CH2—CH2—COOH], which has a retinoid action and is useful as an active ingredient of a medicament.