To obtain an oil-based ink for a ball-point pen capable of providing a handwriting at a constant density without causing a thin or a blurred handwriting.

This oil-based ink for a ball-point pen comprises at least an organic solvent such as glycols or glycol ethers, a colorant such as a dye or a pigment, a resin such as a ketonic resin or polyvinylpyrrolidone and a fluoroalkoxycyclophosponitrile.