The present invention aims to provide compounds which have an inhibitory effect on the binding between S1P and its receptor Edg-1(S1P1) and which are useful for pharmaceutical purposes.A compound represented by formula (I) or a pharmaceutically acceptable salt thereof: [wherein Ar represents a monocyclic heterocyclic ring containing one or two nitrogen atoms, A represents an oxygen atom or the like, Y1, Y2 and Y3 each represent a carbon atom or a nitrogen atom, R1 represents a hydrogen atom, a C1-C6 alkyl group or the like, R2 represents a C1-C6 alkyl group, a C3-C8 cycloalkyl group or the like, R3 represents a C1-C18 alkyl group or the like, R4 represents a hydrogen atom or a C1-C6 alkyl group, and R5 represents a C1-C10 alkyl group or the like].