The present invention discloses a measuring device 1 for measuring an ultra low gas flow, working by the principle of liquid displacement, wherein the measuring device 1 comprises at least one cell 2 comprising a gas inflow means 3, a gas compartment means 4 with a predefined inner geometric physical volume and active volume, the gas compartment means 4 having one gas accumulating end 5 and one lifting end 6, the gas compartment means 4 also defining a geometric gas collecting point inside of the gas compartment means 4 during a gas filling cycle, the geometric gas collecting point moving further and further from the gas accumulating end 5 to the lifting end 6 during the gas filling cycle, and wherein the cell 2 comprises a holding means 7 having a pivoting element 8 enabling the gas compartment means 4 to pivot upwards when the geometric gas collecting point is positioned at the lifting end 6 and the lifting force is larger than the down-pressing force at the lifting end 6, thereby releasing all of the accumulated gas in the gas compartment means 4, and then pivoting back to its initial standby position for new receipt and storage of gas during another gas filling cycle until next releasing sequence, and wherein the cell 2 also comprises a sensor means 9 provided to generate a signal and/or change the state of a signal when the gas compartment means 4 is not in its initial standby position, wherein the gas storing capacity of the inside of the gas compartment means 4 is larger at the gas accumulating end 5 than at the lifting end 6 and wherein the gas accumulating end 5 has a higher vertical position than the lifting end 6 at the initial standby position.