PURPOSE: To feed dampening water of the amount suitable for a printing block and the printing condition by controlling the feeding pressure of dampening water compressively transferred from a dampening water feeding means based on the feeding amount of dampening water stored in a memory by means of a pressure control means.

CONSTITUTION: Dampening water 3 in a storing container 2 is fed from a piping 6 to a piping 9 through an on-off valve 8 by a pump 5, and its pressure is reduced by a primary pressure regulating means 11 through a filter 10. The pressure reduced dampening water 3 from a piping 12 is fed to a secondary pressure regulating means 14. The secondary pressure regulating means 14 is provided with a pressure control valve 15 having an input side port 16 for connecting a piping 12 and an output side port 18 for connecting a piping 17 for pressure regulating the dampening water 3 fed from the input side port 16 and a pressure sensing means 19 for the dampening water 3 in the piping 17. A control circuit 21 for comparing the output from a feeding amount setting device 20 for setting the feeding amount of dampening water 3 fed correspondingly to the printing conditions such as the printing speed, humidity, temperature and the like with the output of the pressure sensing means 19 and issuing a control signal of the pressure control valve 15 is also provided in the device.