Sealing apparatus for sealing a lidding sheet onto a shaped sheet, which has a multiplicity of blister cavities, wherein the sealing apparatus comprises: a sealing roller, which is mounted in a rotatable manner about a sealing-roller axis and has a lateral surface, which has at least one first encircling lateral-surface portion; and a mating roller, which is mounted in a rotatable manner about a mating-roller axis and has a lateral surface, which has at least one first encircling lateral-surface portion, in which apertures are formed for the purpose of accommodating the blister cavities of the shaped sheet, wherein the mating-roller axis is arranged parallel to the sealing-roller axis, and this results in the formation, between the mating roller and the sealing roller, of a gap, through which the shaped sheet and the lidding sheet can be guided in contact with one another; wherein at least one of the rollers made up of the sealing roller and mating roller is mounted such that it can be displaced in the radial direction relative to the other one of the rollers made up of the sealing roller and mating roller, and this results in a distance between the sealing-roller axis and the mating-roller axis being variable; characterized in that, on its lateral surface (16, 20), at least one of the rollers made up of the sealing roller and mating roller has a first group of elevations comprising a plurality of elevations which are spaced apart from one another in the circumferential direction and are elevated in relation to the first lateral-surface portion of the respective roller (10, 12), wherein the first group of elevations is arranged in a second encircling lateral-surface portion of the respective roller (10, 12), this second lateral-surface portion being arranged alongside the first lateral-surface portion of the respective roller (10, 12), as seen in the axial direction; and the distance between the sealing-roller axis and the mating-roller axis corresponds to a first distance when there is no elevation arranged in the region of the gap and to a second distance, which is greater than the first distance, when an elevation is arranged in the region of the gap. a sealing roller, which is mounted in a rotatable manner about a sealing-roller axis and has a lateral surface, which has at least one first encircling lateral-surface portion; and a mating roller, which is mounted in a rotatable manner about a mating-roller axis and has a lateral surface, which has at least one first encircling lateral-surface portion, in which apertures are formed for the purpose of accommodating the blister cavities of the shaped sheet, wherein the mating-roller axis is arranged parallel to the sealing-roller axis, and this results in the formation, between the mating roller and the sealing roller, of a gap, through which the shaped sheet and the lidding sheet can be guided in contact with one another; wherein at least one of the rollers made up of the sealing roller and mating roller is mounted such that it can be displaced in the radial direction relative to the other one of the rollers made up of the sealing roller and mating roller, and this results in a distance between the sealing-roller axis and the mating-roller axis being variable; characterized in that, on its lateral surface (16, 20), at least one of the rollers made up of the sealing roller and mating roller has a first group of elevations comprising a plurality of elevations which are spaced apart from one another in the circumferential direction and are elevated in relation to the first lateral-surface portion of the respective roller (10, 12), wherein the first group of elevations is arranged in a second encircling lateral-surface portion of the respective roller (10, 12), this second lateral-surface portion being arranged alongside the first lateral-surface portion of the respective roller (10, 12), as seen in the axial direction; and the distance between the sealing-roller axis and the mating-roller axis corresponds to a first distance when there is no elevation arranged in the region of the gap and to a second distance, which is greater than the first distance, when an elevation is arranged in the region of the gap.