A non-aqueous ink for a ball point pen is disclosed herein which is accompanied by the feature of the non-aqueous ink excellent in the so-called cap-off performance that a writing performance does not deteriorate even when the pen is allowed to stand, with a cap being removed, and the feature of an aqueous ink that a low writing pressure can be used and blobbing does not occur. This ink comprises an organic solvent having a vapor pressure of 0.2 mmHg (20°C) or less, a colorant and a coagulant and has a non-Newtonian viscosity index of 0.2 to 0.5 and a viscosity of 200 mPa·s (25°C, 50 rpm) or less. Furthermore, the ink is characterized by containing a autolyophobic vehicle in which a contact angle to the surface of a material such as stainless steel or bronze having a high surface free energy is in the range of 5 to 40°.