A method for removing a blade ring accommodated in a casing forming the shell of a turbine, wherein the blade ring has a two-piece construction including an upper half section and a lower half section, and wherein the casing has a two-piece construction including an upper half section and a lower half section, the method comprising: a first step of removing the upper half section of the casing to make an upper portion of the lower half section of the casing open; a second step of removing the upper half section of the blade ring; a third step of connecting a dummy blade ring having almost the same shape as that of the upper half section of the blade ring to the lower half section of the blade ring accommodated in the lower half section of the casing with a connection member being interposed between the lower half section of the blade ring and the dummy blade ring; a fourth step of rotating the lower half section of the blade ring and the dummy blade ring so that the lower half section of the blade ring projects above from the lower half section of the casing; and a fifth step of removing the lower half section of the blade ring, which projects above from the lower half section of the casing, from the dummy blade ring, wherein in the third step, the dummy blade ring and the connection member are connected to each other by a first connecting bolt capable of being rotated from both of the dummy blade ring side and the connection member side, and the connection member and the lower half section of the blade ring are connected to each other by a second connecting bolt, and in the fifth step, the dummy blade ring and the connection member are separated from each other by rotating the first connecting bolt from the connection member side, and the lower half section of the blade ring and the connection member are removed from the dummy blade ring. a first step of removing the upper half section of the casing to make an upper portion of the lower half section of the casing open; a second step of removing the upper half section of the blade ring; a third step of connecting a dummy blade ring having almost the same shape as that of the upper half section of the blade ring to the lower half section of the blade ring accommodated in the lower half section of the casing with a connection member being interposed between the lower half section of the blade ring and the dummy blade ring; a fourth step of rotating the lower half section of the blade ring and the dummy blade ring so that the lower half section of the blade ring projects above from the lower half section of the casing; and a fifth step of removing the lower half section of the blade ring, which projects above from the lower half section of the casing, from the dummy blade ring, wherein in the third step, the dummy blade ring and the connection member are connected to each other by a first connecting bolt capable of being rotated from both of the dummy blade ring side and the connection member side, and the connection member and the lower half section of the blade ring are connected to each other by a second connecting bolt, and in the fifth step, the dummy blade ring and the connection member are separated from each other by rotating the first connecting bolt from the connection member side, and the lower half section of the blade ring and the connection member are removed from the dummy blade ring.