The present invention provides a sheath for a disposable dental direct imaging digital device. The sheath for a disposable dental direct imaging digital device includes a bag structure that is made up of an elastic material, and is also made up of a positioning device that is placed in an opening of the bag structure. A direct imaging digital device may be inserted into the sheath. A first housing segment that is in connection with the opening exists on one end of the bag structure. The other end of the first housing segment is in connection with a second housing segment. A tapered channel is formed from the opening of the first housing segment towards the second housing segment. A positioning device may close or shrink the opening, so as to prevent the direct imaging digital device from sliding out of the sheath. The direct imaging digital device may be inserted into the first housing segment, and then may be inserted into the second housing segment. Accordingly, the direct imaging digital device may be encapsulated and positioned by the second housing segment. In accordance with the present invention, the time of insertion the direct imaging digital device into the sheath may be shortened, and ease of use of the sheath with the direct imaging digital device may be enhanced. Moreover, the sheath of the present invention may be suitable for a direct imaging digital device of any size.本發明拋棄式牙科直接顯像數位器護套包含由彈性材料構成的袋體結構以及設於袋體結構開口端的定位裝置，其內部可置入一直接顯像數位器，其中，袋體結構設有端部與開口連通的第一容置區段，並由第一容置區段另一相對端部連通第二容置區段，將第一容置區域設計由開口朝向第二容置區段形成漸縮通道；定位裝置能夠將護套開口加以封閉或是縮小範圍，避免置入其中的直接顯像數位器滑出，當直接顯像數位器由護套開口滑入第一容置區段再將第二容置區段撐張進入而被包覆定位，如此即可縮短將直接顯像數位器套入護套的時間以及使用便利性，並讓護套適用於任意規格大小的直接顯像數位器。
