The invention provides an oil composition, in which the thiamine is used to convert the vitamin B1 derivative or its salt containing 44-8000 ppm and the hydroxyl value is 9-100 mg KOH / g, and the content C (PPM) converted by thiamine and the hydroxyl value x (mg KOH / g) of the vitamin B1 derivative or its salt meet the relationship of formula (1):(number 1)[ln (C / 143)] / X u2264 0.044 (LN: natural logarithm) (1).本發明提供一種油脂組合物,其係以硫胺換算含有44~8,000 ppm之維生素B1衍生物或其鹽且羥值為9~100 mg-KOH/g者,維生素B1衍生物或其鹽之以硫胺換算之含量C(ppm)與羥值X(mg-KOH/g)滿足下式(1)之關係:(數1)[Ln(C/143)]/X≦0.044 (Ln:自然對數) (1)。