A scanning exposure device includes a stage that supports a substrate, wherein a space is provided between a stage surface and the substrate; a light source unit that radiates light to a light irradiation area that extends in one direction above the substrate; and a scanning device that moves one or both of the stage and the light source unit relatively in a scanning direction that intersects the one direction. The scanning device is provided with an acceleration zone from a position in which the stage and the light source unit are at a standstill to a position in which the substrate supported by the stage enters the light irradiation area. The stage comprises a light shielding member that covers the space between the stage surface and the substrate at an end part of the stage.