In a folding screen device pulled in the lateral direction, the widthwise dimension limit of the screen device in the opening and closing direction of the screen is eliminated. A plurality of screen units include movable vertical frame members attached to both ends of a screen expandable in an accordion manner. The vertical frame members are slidable along a lateral frame member of a building opening. Screen guides in the screen units move out and into the interior of the vertical frame member through upper and lower ends thereof in a bent state, and are led along upper and lower ends of the screen in an extended state. A parallel movement mechanism causes the vertical frame members to move in parallel during opening and closing of the screen. The screen units can be arranged in parallel in the building opening by connecting adjacent vertical frame members of the screen units.