Rotationally driven poppet valve

Valve device is provided with poppet valve for opening and closing flow path. Thread part is formed on shaft of this poppet valve, and driving gear is screwed into this thread part. Driving gear is rotated via pinion by motor, and thereby the poppet valve is moved to advance and retreat so as to control opening and closing of the flow path. Driving gear is provided so as to be able to advance and retreat in the axial direction of the pinion and the axial direction of the poppet valve while remaining engaged with pinion, and is normally held at a predetermined non-operating position by spring (biasing means). With this, even when the poppet valve is seated on the valve seat and has stopped moving, the driving gear moves, when further rotated, against the biasing force of spring from the non-operating position in the axial direction, and absorbs an impact that is applied to the driving means or the like. Damage of the driving means and the like due to the impact load can be prevented.