A gas flow measuring device (101 ) has a housing (121, 123) comprising a gas inlet (124) and a gas outlet (122). A valve with an adjustable restriction (103) and an actuator (107) for adjusting the restriction (103) is arranged between the gas inlet (124) and the gas outlet (122) for restricting the gas flow from the gas inlet (124) to the gas outlet (122). The restriction (103) comprises a substantially circular-shaped rotatable disc (105) having a first and an opposite second disc surface, and at least one disc passage (1 10); and a mount (106) having a mount surface (126) facing and contacting the first disc surface (1 16), and a mount passage (1 1 1 ). At least one of the first disc surface (1 16) and the mount surface (126) comprises a ring-shaped area (130) extending above the surface thereof contacting the other one of the first disc surface (1 16) and the mount surface (126). The mount (106) further comprises a ring-shaped part (104) contacting the second disc surface (1 12).