To provide a rubber roller for offset printing capable of always stably conducting printing of high quality and preventing a trouble at the time of printing for a long period, and to provide an offset printer incorporated with the roller.

The rubber roller for offset printing is used for a water supply unit of the offset printer. The rubber roller comprises a coating layer formed on a surface of a rubber and having a lower layer formed of a composition (A) containing a compound having two or more photopolymerization initiating groups in one molecule and a monomer having two or more radical polymerizable functional groups, and an upper layer formed of a composition (B) containing a water soluble radical polymerizable monomer in such a manner that the upper layer and the lower layer are chemically bonded.