The present invention provides novel esterified ±-galactosylceramides effective for cancer treatment and the like, and a medicament containing same. The present invention relates to a compound represented by the formula (I): wherein R 1 is a hydrocarbon group having a carbon number of 1 to 30, R 2 is a hydrocarbon group having a carbon number of 1 to 20, R 3 is a hydrogen atom or hydrocarbon group having a carbon number of 1 to 5, R 4 and R 5 are the same or different and each is a hydrogen atom or a hydrocarbon group having a carbon number of 1 to 5, or R 4 and R 5 in combination form a divalent hydrocarbon group having a carbon number of 1 to 5, and optionally form a ring structure together with the adjacent ethylenedioxy, or a salt thereof.
