An exposure apparatus that has an illumination optical system configured to illuminate a mask with illumination light and a projection optical system configured to project a pattern image of the mask onto a substrate, and is configured to perform a scanning exposure of the substrate by moving each of the mask and the substrate relative to the illumination light, the apparatus comprising: a first base member arranged above the projection optical system and having a first opening section through which the illumination light is arranged to pass; a first stage system that has a slider, a movable member and a first drive system, the slider being arranged on the first base member, the slider having a second opening section through which the illumination light is arranged to pass and a support member for supporting the mask in the second opening section, the movable member being arranged on the first base member and being provided so as to surround the slider, with the slider vertically not extending beyond the movable member, the first drive system having a first motor and being configured to move the slider surrounded by the movable member, and the first motor having a movable element provided at the slider and a stator provided at the movable member; a second base member arranged below the projection optical system; a second stage system that has a stage and a second drive system, the stage being arranged on the second base member and having a holder for holding the substrate, the second drive system having a second motor configured to drive the stage, and the second drive system being configured to move the stage on the second based member; and a controller configured to control the first and the second drive systems so that the mask and the substrate are each moved relative to the illumination light in a first direction orthogonal to the optical axis of the projection optical system, during the scanning exposure, wherein the movable member is arranged to be moved by a reaction force generated by a movement of the slider by the first drive system, and an airtight space, through which the illumination light is arranged to pass when exposure of the substrate is performed, is formed above the first base member, and the movable member is also used as a partition wall that divides the airtight space from the outside air. a first base member arranged above the projection optical system and having a first opening section through which the illumination light is arranged to pass; a first stage system that has a slider, a movable member and a first drive system, the slider being arranged on the first base member, the slider having a second opening section through which the illumination light is arranged to pass and a support member for supporting the mask in the second opening section, the movable member being arranged on the first base member and being provided so as to surround the slider, with the slider vertically not extending beyond the movable member, the first drive system having a first motor and being configured to move the slider surrounded by the movable member, and the first motor having a movable element provided at the slider and a stator provided at the movable member; a second base member arranged below the projection optical system; a second stage system that has a stage and a second drive system, the stage being arranged on the second base member and having a holder for holding the substrate, the second drive system having a second motor configured to drive the stage, and the second drive system being configured to move the stage on the second based member; and a controller configured to control the first and the second drive systems so that the mask and the substrate are each moved relative to the illumination light in a first direction orthogonal to the optical axis of the projection optical system, during the scanning exposure, wherein the movable member is arranged to be moved by a reaction force generated by a movement of the slider by the first drive system, and an airtight space, through which the illumination light is arranged to pass when exposure of the substrate is performed, is formed above the first base member, and the movable member is also used as a partition wall that divides the airtight space from the outside air.