A compound represented by the following formula (1): wherein R1 is an aldopyranose residue wherein the 6-hydroxyl group is optionally alkylated, R2 is a C1-26 hydrocarbon group optionally having substituent(s), R3 is a hydrogen atom or a C1-26 hydrocarbon group optionally having substituent(s), R4 is a C1-21 hydrocarbon group optionally having substituent(s), X is an oxygen atom or —CH2—, and Y is —CH2—, —CH(OH)— or —CH═CH—, or a salt thereof is useful for the prophylaxis or treatment of cancer or infection, since it can preferentially induce production of IFN-γ of NKT cells.