An oil composition containing 70 to 100% by mass of an oil composition (A) which is mainly composed of a steradiene having a 3, 5-conjugated diene structure formed by dehydrating a hydroxyl group at 3-C of phytosterol, while having a phytosterol content of 20% by mass or less, and which is liquid at 25° C., and 0 to 30% by mass of an oil (B) which is soluble in the oil composition (A) has excellent transparency and gloss imparting property, and is useful as an oily base to produce an external preparation for skin. An external preparation for skin which contains the oil composition as an oil base is excellent in gloss and adhesion. The content of the steradiene in the oil composition (A) is usually 60% by mass or more, and is preferably 95% by mass or more.
