The phenomenon of turbulent cavitating flow, with phase change, becomes more complicated taking into account the non-condensable gas as an additional phase. The water, which is the operating fluid, contains a specified amount of dissolved air; as a result, the cavitating flow needs to be considered as a three-phase (i.e. water, vapor and air) flow. Although the existence of dissolved air is well known, most numerical models neglect it; as such, its effect is usually underestimated so far. To this end, the present work is devoted to developing a modified cavitation model based on the merging theory, taking into account the dissolved air in an Eulerian approach. The diffusion process is modeled to constitute the new bubble of the mixture; as a result, the bubble pressure is corrected based on the local air level.