Surface cleaning machine with moistening

There is provided a surface cleaning machine, comprising at least one cleaning roller (18), drive means (76) for rotary driving of the at least one cleaning roller (18), a moistening device (116) for acting on the at least one cleaning roller (18) with cleaning fluid, and a Saugaggregateinrichtung (32) for generating a suction flow, which with at least one suction channel (44) and at least one suction mouth (54) that is associated with the at least one cleaning roller (18) is in fluid connection, wherein the moistening device (116) at least one pressure-controlled switch (118) releases which a fluid path in an opened position (146) for cleaning fluid to the at least one cleaning roller (18) and in a closed position the fluid path (146) blocks, and the at least one pressure-controlled switch (118) pressure effective gekoppe to the at least one suction channel (44) lt, wherein caused by a suction flow in the at least one suction channel (44) of vacuum to the at least one pressure-controlled switch (118) in the open position is at one and / or maintains the open position.