To obtain a binder resin assuring the highest luster of ink coating film on a material to be printed even at relatively high printing speed.

This binder resin is composed of the constituents of the following respective compounds: (A) natural resin and natural resin acid, (B) aldehyde and aldehyde acetal, (C) α,β-ethylenically unsaturated carboxylic acid and its anhydride, (D) phenols, (E) alcohol bearing at least two hydroxyl groups, and, optionally, one or more kinds of compounds shown as follows: (F) monovalent, divalent or trivalent metal salt, (G) fatty acid and fatty acid ester, and (H) ethylenically unsaturated hydrocarbon resin. This binder resin is obtained by reaction of the compound A with the compound B followed by the compounds C, D and E, and, optionally, one or more kinds of the respective compounds (F), (G) and (H) at 100-300°C while removing water.