Abstract: A fluid mixing device is formed as a one-piece unit having opposite inlet and outlet ends, a first, inlet bore portion extending from the inlet end for connection to a supply of a primary fluid under pressure, an outlet bore portion extending up to the outlet end, and a pair of spaced, relatively short, cylindrical venturi passageways of reduced cross-sectional dimensions extending from the inlet bore portion to the outlet bore portion, each venturi passageway having a throat. The unit has a first transverse inlet communicating with the first venturi passageway adjacent the throat for connection to a supply of a first secondary fluid and a second transverse inlet adjacent the throat of the second venturi passageway for connection to a supply of a second secondary fluid, whereby the secondary fluids are drawn into the primary fluid stream flowing in the respective venturi passageways.