A moistening nozzle of a paper web comprises a frame (1) into which air and water are conducted. Inside the frame (1) there is arranged a water nozzle (2) wherewith water is conducted to an outlet of the moistening nozzle and an air nozzle wherewith air is correspondingly conducted to the outlet. The air nozzle (3) and the water nozzle (2) are arranged one within the other such that the air and the water form water mist that is blown out from the moistening nozzle. The air nozzle (3) is provided with an inner thread (10) that brings the air in swirling motion.