A casing including a first casing body, a second casing body, at least one first linkage, and a second linkage is provided. The first casing body has a first end portion. The second casing body is movably connected to the first casing body, wherein the second casing body has a second end portion, and the first end portion and the second end portion are abutted against each other or separated from each other. The first linkage is disposed adjacent to the first end portion and pivoted to the first casing body. The second linkage is disposed adjacent to the second end portion, wherein the second linkage is pivoted to the second casing body and the first linkage, and the first casing body and the second casing body are respectively located at two opposite sides of the first linkage and the second linkage.