To provide a method for offset printing with which an original printing plate is easily made up without use of an alkaline developing solution and with a print quality improved at a practical level in distinguishability between an image part and a non-image part of a printed face, and can be repeatedly used.

In this method and an apparatus for offset printing, the original printing plate is made hydrophilic when heated at a temperature required for developing high temperature hydrophilicity. Then, on a surface of the plate a hydrophobic image area is formed by imagewise coating with an ink-jet method a solution including at least one of chemical compounds expressed by GnJM4-n (G is a hydrophobic organic group; J is an element with an atomic value of 4 selected out of C, Si, Ge, Ti, Zr, and Sn; M is halogen or an alkoxy group; and (n) is an integer of 1 to 3). A method and an apparatus for reusing the original printing plate after the surface of the plate used is cleaned so that the remaining ink is removed, then the chemical compound is thermally decomposed, are also provided.