To provide the attaching and detaching device of the transfer roll of a printing machine, in which no hicky removing work can be performed under a state, in which an inking roller and the transfer roller are brought into contact with each other.

The attaching and detaching device of the transfer roller of the printing machine comprises a plate cylinder 9, the inking roller 10 for supplying ink to the plate cylinder 9, a dampening roller 12 for giving dampening water to the plate cylinder 9, and the transfer roller 11, which is provided attachably to and detachably from the inking roller 10 under the state being in contact with the dampening roller 12, wherein the inking roller 10 and the transfer roller 11 are brought in a state being separated from each other when the dampening roller 12 and the plate cylinder rotate in their surface speeds different from each other.