To provide an oleaginous ball-point pen, which gives a smooth writing touch and with which a handwriting can be carried out by a good holograph with neither line-splitting nor bleeding nor feathering to a paper face.

In an ink for an oleaginous ball-point pen including a colorant, an organic solvent, a non-Newtonian viscosity imparting agent, a non-Newtonian viscosity index is set to be 0.5 or less, the viscosity at the shearing speed of 500 s-1 at 20°C is set to be 100-2,000 mPa.s. By housing this ink in an ink housing tube or a shaft tube equipped with a ball-point pen tip rotatably holding a ball having an arithmetic mean surface roughness Ra of 0.004-0.010 μm, an oleaginous ball-point pen is obtained.