A compound represented by formula (I) or a pharmaceutically acceptable salt thereof: (wherein Y1 represents a nitrogen atom or a group represented by CRA, Y2 represents a nitrogen atom or a group represented by CRB, Y3 represents a nitrogen atom or a group represented by CRC, RA, RB and RC, which may be the same or different, each represent a hydrogen atom, etc. (excluding the case where Y1 is CRA, Y2 is CRB and Y3 is CRC), X represents an oxygen atom, etc., R1 represents a C1-C6 alkyl group, etc., R2 represents a C1-C6 alkyl group, etc., R3 represents an optionally substituted phenyl group, etc., R4 represents a hydrogen atom, etc., and R5 represents an optionally substituted phenyl group, etc.) has an inhibitory effect on the binding between S1P and its receptor Edg-1(S1P1), and is useful as a therapeutic agent for autoimmune diseases, rheumatoid arthritis, asthma, atopic dermatitis, rejection after organ transplantation, cancer, retinopathy, psoriasis, osteoarthritis, or age-related macular degeneration, etc.