This oily composition contains: 70-100% by mass of an oily composition (A) which is mainly composed of a steradiene having a 3, 5-conjugated diene structure converted from a phytosterol by means of dehydration of a hydroxyl group in the 3-position, while having a phytosterol content of 20% by mass or less, and which is in a liquid state at 25°C； and 0-30% by mass of an oil (B) which is soluble with the oily composition (A). This oily composition has excellent transparency and gloss imparting properties, and is useful as an oil-based base agent for external preparations for the skin. An external preparation for the skin according to the present invention, which contains this oily composition as an oil-based base material, has excellent gloss and adhesiveness. In addition, the content of the steradiene in the oily composition (A) is usually 60% by mass or more, and is particularly preferably 95% by mass or more.
