Thermally shrinkable wrapper, in particular for use in sterilization process, said wrapper comprising: - a first layer consisting of thermally shrinkable film in the form of endless band of pre-determined with and with linear longitudinal edges (11, 12) defining a longitudinal direction of the wrapper; - a second layer consisting of thermally shrinkable film in the form of endless band of pre-determined width and with two linear longitudinal edges (21, 22), which is placed over said first layer, so that both pairs of longitudinal edges (11, 12; 21, 22) are aligned with each other; - a pair of bearing bands (31, 32) consisting of thermally non-shrinkable material, wherein each of them is integrated and welded between said first layer and said second layer in the area of their aligned longitudinal edges (11, 12; 21, 22), wherein each of said thermally shrinkable layers (1, 2) is furnished with a plurality of perforations, which are arranged in the form of an uniform raster along the lines, which extend equidistantly with respect to each other in the transversal direction of the wrapper and are also equidistantly arranged in the longitudinal direction of the wrapper, and wherein each connecting area between each bearing band (31, 32) and said first and second layer (1, 2) is formed of groups of welds (500, 500', 500"), which are equidistantly spaced apart from each other in the longitudinal direction of the wrapper and are present on both bearing bands (31, 32) as well as on both layers (1, 2) adjacent to said longitudinal edges (11,12; 21, 22) thereof, so that each group of welds (500, 500', 500") comprises at least two welds (500, 500', 500"), which each per se extend in the longitudinal direction of the wrapper and are spaced apart from each other in the transversal direction of said wrapper. - a first layer consisting of thermally shrinkable film in the form of endless band of pre-determined with and with linear longitudinal edges (11, 12) defining a longitudinal direction of the wrapper; - a second layer consisting of thermally shrinkable film in the form of endless band of pre-determined width and with two linear longitudinal edges (21, 22), which is placed over said first layer, so that both pairs of longitudinal edges (11, 12; 21, 22) are aligned with each other; - a pair of bearing bands (31, 32) consisting of thermally non-shrinkable material, wherein each of them is integrated and welded between said first layer and said second layer in the area of their aligned longitudinal edges (11, 12; 21, 22), wherein each of said thermally shrinkable layers (1, 2) is furnished with a plurality of perforations, which are arranged in the form of an uniform raster along the lines, which extend equidistantly with respect to each other in the transversal direction of the wrapper and are also equidistantly arranged in the longitudinal direction of the wrapper, and wherein each connecting area between each bearing band (31, 32) and said first and second layer (1, 2) is formed of groups of welds (500, 500', 500"), which are equidistantly spaced apart from each other in the longitudinal direction of the wrapper and are present on both bearing bands (31, 32) as well as on both layers (1, 2) adjacent to said longitudinal edges (11,12; 21, 22) thereof, so that each group of welds (500, 500', 500") comprises at least two welds (500, 500', 500"), which each per se extend in the longitudinal direction of the wrapper and are spaced apart from each other in the transversal direction of said wrapper.