An offset printing ink in which a modified pigment (D) is dispersed in a vehicle as a colorant, the modified pigment (D) contains a polymer (P) on the surface thereof, and the polymer (P) is obtained by polymerizing a resin or fat (B) which has a polymerizable unsaturated group, and is soluble in a nonaqueous solvent, and at least one of polymerizable unsaturated monomers (C) which are soluble in a nonaqueous solvent and insoluble or poorly-soluble after polymerization, and specifically, the resin or fat (B) is selected from the group consisting of acrylic resins having a polymerizable unsaturated group, alkyd resins which are soluble in the nonaqueous solvent, natural resin-modified phenol resins, and fats.