A vacuum toilet system having means to diminish stains generated on a lower surface of a shroud when flush is operated with lid closed. The toilet system is structured to make air flow easier into the bowl when lid is closed. The lid is provided with mesh, slit, or air scoop style openings. The system also provides a structure in which flush operation is triggered by detecting a predetermined inclining angle of the lid before it closes. Another aspect is that the lower surface of the shroud is curved for keeping shroud away from the upper surface around the bowl's rim. Another aspect is that the height of the shroud stays extending from the shroud's lower surface is higher compared to the prior art. The system also provides protrusions projecting upward from the bowl's upper surface opposite the shroud stays in a wavy configuration around the bowl's rim.