A modularized server, comprising: a rack, comprising a first slot and a second slot; a switching mechanism, comprising: a switching element, movably disposed on the rack; a first stopping block, disposed on the switching element, and extending into the first slot; a second stopping block, disposed on the switching element, and extending into the second slot; and an elastic element, disposed on the rack and the switching element, for providing an elastic force to maintain the switching element, the first stopping block, and the second stopping block at an initial position; wherein the first slot is operable to receive a first removable electronic device, the first removable electronic device comprising: a first casing; and a first limiting element, disposed on the first casing; wherein, when the first removable electronic device is inserted into the first slot and the first limiting element is disposed at a first marked position on the first casing, the first limiting element is operable to push the first stopping block, such that the switching element, the first stopping block, and the second stopping block move to a first switching position, wherein, when the first removable electronic device is inserted into the first slot and the first limiting element is disposed at a second marked position on the first casing, the first limiting element is operable to push the first stopping block, such that the switching element, the first stopping block, and the second stopping block move to a second switching position, wherein the first switching position and the second switching position are different. a rack, comprising a first slot and a second slot; a switching mechanism, comprising: a switching element, movably disposed on the rack; a first stopping block, disposed on the switching element, and extending into the first slot; a second stopping block, disposed on the switching element, and extending into the second slot; and an elastic element, disposed on the rack and the switching element, for providing an elastic force to maintain the switching element, the first stopping block, and the second stopping block at an initial position; wherein the first slot is operable to receive a first removable electronic device, the first removable electronic device comprising: a first casing; and a first limiting element, disposed on the first casing; wherein, when the first removable electronic device is inserted into the first slot and the first limiting element is disposed at a first marked position on the first casing, the first limiting element is operable to push the first stopping block, such that the switching element, the first stopping block, and the second stopping block move to a first switching position, wherein, when the first removable electronic device is inserted into the first slot and the first limiting element is disposed at a second marked position on the first casing, the first limiting element is operable to push the first stopping block, such that the switching element, the first stopping block, and the second stopping block move to a second switching position, wherein the first switching position and the second switching position are different. a switching element, movably disposed on the rack; a first stopping block, disposed on the switching element, and extending into the first slot; a second stopping block, disposed on the switching element, and extending into the second slot; and an elastic element, disposed on the rack and the switching element, for providing an elastic force to maintain the switching element, the first stopping block, and the second stopping block at an initial position; wherein the first slot is operable to receive a first removable electronic device, the first removable electronic device comprising: a first casing; and a first limiting element, disposed on the first casing; wherein, when the first removable electronic device is inserted into the first slot and the first limiting element is disposed at a first marked position on the first casing, the first limiting element is operable to push the first stopping block, such that the switching element, the first stopping block, and the second stopping block move to a first switching position, wherein, when the first removable electronic device is inserted into the first slot and the first limiting element is disposed at a second marked position on the first casing, the first limiting element is operable to push the first stopping block, such that the switching element, the first stopping block, and the second stopping block move to a second switching position, wherein the first switching position and the second switching position are different. a first casing; and a first limiting element, disposed on the first casing; wherein, when the first removable electronic device is inserted into the first slot and the first limiting element is disposed at a first marked position on the first casing, the first limiting element is operable to push the first stopping block, such that the switching element, the first stopping block, and the second stopping block move to a first switching position, wherein, when the first removable electronic device is inserted into the first slot and the first limiting element is disposed at a second marked position on the first casing, the first limiting element is operable to push the first stopping block, such that the switching element, the first stopping block, and the second stopping block move to a second switching position, wherein the first switching position and the second switching position are different.