A downhole valve device (1) of the kind used in a drill string (14) in a well (2) in the exploration and recovery of petroleum deposits, comprising a valve housing (20) and a valve (23), there being disposed in the drill string (14) one or more downhole valve(s) (1) which are arranged to open/close to a branching of fluid out from the cavity of the drill string (14) into an annulus (3', 4') formed between the drill string (14) and the well wall.