To provide a valve device which prevents or reduces defects such as generation of its abnormal sounds.

A switching device used for a circuit for pressure-feeding air to a septic tank displaces a position of a valve member 34 from a first state to a second state by drawing a movable iron core 37 to a fixed iron core 38 side. While the movable iron core 37 and the fixed iron core 38 are separated from each other in the second state, a contact state of the valve member 34 to a second valve seat member 32s is maintained by a latch member 40.