A novel metering device (1) for dispensing a dose of a pressurized fluid is described. A dispensing valve body (3) is mounted in a fluid-tight manner to the lid (4) of a pressurized container (5), which circumvents a valve element (9). A valve delivery tube (10) is connected to the valve element (9). A chamber (13) surrounds the valve body (3), in which a piston (17) is reciprocable between an upper and a lower position, which define the dispensing dose. A clearance is provided between the piston (17) and the inner wall (23) of the chamber (13), such that pressurized fluid can flow into the chamber based on a pressure difference between the container (5) and the chamber (13), and the piston (17) is adapted to seal the valve body (3) when being in the upper position.