The present invention aims to provide compounds which have an inhibitory effect on the binding between S1P and its receptor Edg-1(S1P 1 ) 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, Y 1 , Y 2 and Y 3 each represent a carbon atom or a nitrogen atom, R 1 represents a hydrogen atom, a C 1 -C 6 alkyl group or the like, R 2 represents a C 1 -C 6 alkyl group, a C 3 -C 8 cycloalkyl group or the like, R 3 represents a C 1 -C 18 alkyl group or the like, R 4 represents a hydrogen atom or a C 1 -C 6 alkyl group, and R 5 represents a C 1 -C 10 alkyl group or the like].
