To provide an oil-based marking pen in which even an ink composition having small surface tension is stored with a high retension property and an ink flow out property.

An oil-based marking pen is obtained by using an ink stored material composed by focusing a filament of 2.5 or under denier thickness in 0.15 to 0.25 g/cc density. Further, as an ink composition wherein surface tension is small and it is suitable for the oil-based marking pen (for example, a fixing property of a film is high), an ink composition containing silicone polymer surfactant (for example, polyoxypolypropylene modified silicone, carboxyl modified silicone, etc.) can be exemplified.