To prevent dampening water from being decomposed and polluted and further prevent printing trouble from developing caused by the variation of raw water used as the dampening water.

This dampening water feeding device has a device for feeding the dampening water to the cistern of a printing machine and a device for detecting and maintaining the water level of the amount of the dampening water in the cistern so as to improve printing quality by providing a dampening water feeding system, which feeds the dampening water only from one direction from the feeding device to the system and has no return of the dampening water from the cistern to the feeding device in order to prepare the dampening water by using the raw water predetermined beforehand.