Abstract: Both surfaces of a substrate formed with a resist or a thin film sample can be exposed concurrently and either one surface exposure or both surface concurrent exposure of the sample can be carried out. The first groove for use in fixing the flat plate holder of transparent material held by a frame to the frame under a suction of vacuum and fixing is formed at a lower circumferential edge of the flat plate holder, the second groove for sucking by vacuum and fixing the mask film on the upper surface of the flat plate holder is formed at the upper surface of the flat plate holder and at the same time there is provided a seal member for sealing a clearance between the mask film and the end part of the sample formed with a resist position aligned to each other, and suction holes for use in sucking by vacuum and fixing the lower surface of the end part of the sealed sample are communicated with each of the seal member, mask film and the flat plate holder in a sample holding device of the exposure device.