[Problem] An ester compound having low viscosity, excellent fluidity even at low temperatures, and a high viscosity index; and a lubricating oil base oil containing said compound are provided. [Solution] The present invention provides an ester compound indicated by formula (I). Formula (I) (in formula (I), R1 is a hydrocarbon group having 1 to 35 carbon atoms and at least one hydrogen in the hydrocarbon group may be independently substituted with a group indicated by formula (II)). Formula (II) (in formula (II), R2 is a linear alkyl having 1 to 30 carbon atoms or a branched alkyl having 3 to 30 carbon atoms.)