A valve device for opening and closing a valve including a movable valve member, the valve device comprising: an operation member movable toward and away from the valve, the operation member moving the valve member with magnetic force when moving toward or away from the valve to open or close the valve, wherein the operation member is formed to move in a predetermined direction including a first component representing magnitude of a vector in a movement direction of the valve member and a second component representing magnitude of a vector in a direction perpendicular to the movement direction of the valve member, with the first component being greater than the second component.