Abstract: The apparatus for growing organisms by moist air comprises the closed moistening tank having water therein, and the mixing chamber on the surface of said water, the nozzle and air pump for releasing air bubbles into the said water, the moist air outlet provided on the said mixing chamber, and the air feed tube connected with the said moist air outlet for passing the moist air into the culture medium.Within the said mixing chamber, watery components are caused to adhere to the surfaces of ascending bubbles in the water. Mist is formed from the rupture of these bubbles, Adjustment is made for selecting the mist of small particle size. Then, there is prepared the moist air containing almost uniformly the mist of small particle size by a high pressurization within the said mixing chamber. Such moist air is caused to pass through the air feed tube in the form of a nearly laminar flow into the culture medium.