A sheet jig relating to the present invention is provided with: a center placing surface (17) for placing a center portion of a sheet (50); an outer peripheral upper surface (18), which is disposed on the outer side of the center placing surface (17), and which is formed lower than the height of the center placing surface (17); and a sloped surface (19) that is provided toward the outer peripheral upper surface (18) from the center placing surface (17). The center placing surface (17) has a plurality of first air holes (13) for sucking the center portion of the sheet (50), and the outer peripheral upper surface (18) has a plurality of second air holes (14) for sucking an outer peripheral portion of the sheet (50).