To provide a small and quiet negative pressure generating device capable of being installed in a room in a hospital.

A jet pump M.J.P is formed of a pressuring means for sucking and pressurizing liquid in a container 9, a liquid injection nozzle 12 for injecting liquid pressurized by the pressurizing means, a negative pressure forming pipe 12 for forming negative pressure by fluid injected from the liquid injection nozzle 12, and a suction port communicated with a suction pipe 7 at a negative pressure forming part of a negative pressure forming pipe 13, the jet pump M.J.P is housed in the container in which liquid is stored, at least one part of the jet pump M.J.P is submerged in liquid stored in the container 9, and vibration and noise generated on the jet pump M.J.P are sucked to the liquid in the container.