The present invention relates to (1) a stabilized oil-based thickening gel composition comprising (a) an anionic surfactant having a lipopeptide structure, (b) water and/or a polyhydric alcohol having a valence of 3 or more, (c) a tocopherol compound and (d) an oil component, (2) a method for improving storage ability of an oil-based thickening gel composition characterized by addition of (c) tocopherol compound to an oil-based thickening gel composition comprising (a) a anionic surfactant having a lipopeptide structure, (b) water and/or a polyhydric alcohol having a valence of 3 or more and (d) an oil component, and (3) a cosmetic comprising the oil-based thickening gel composition.