An oily ink for writing instruments comprising e. colorant, f. resin, g. an organic solvent and h. a gelling agent, wherein the said gelling agent comprises a soluble gelling agent with the solubility of from about 0.1 to about 20% by weight at a temperature of 20.degree. C. to the said organic solvent, and the viscosity of the ink is not less than 700 mPa.multidot.s when the rate of shear is 0.1 (1/s) and not greater than 500 mPa.multidot.s when the rate of shear is 100 (1/s).