Disclosed is a grease composition containing a base oil composed of a fluorine-containing synthetic oil, which is characterized in that an aliphatic dibasic acid salt represented by the following general formula (1): (CH2)n(COO)2Mm (wherein n represents an integer of 1-19; M represents an alkali metal or an alkaline earth metal; and m is 2 when M represents an alkali metal, while m is 1 when M represents an alkaline earth metal) is contained as a rust inhibitor in an amount of not less than 0.1% by mass but less than 1.0% by mass. Also disclosed is a bearing in which the grease composition is sealed. The composition is a fluorine-containing grease composition having excellent antirust properties and reduced environmental burden, and is suitable for rolling bearings used under high temperature conditions.