This invention discloses a network device including at least one rail element disposed at both sides of the network device at positions adjacent to the rear of the network device respectively to form a slide rail on each side, and two fixing elements each having a locking portion and a support portion, wherein the locking portion has at least one locking hole and is coupled perpendicularly to the support portion, such that when the network device is installed in a rack and the front of the network device is fixed to the front of the rack, each support portion can be extended into each corresponding slide rail, and each locking portion can be secured to the rear of the rack through each corresponding locking hole.