Abstract: A portable apparatus includes an electronic device; and a fastening device detachably attached to the electronic device. The fastening device includes a cover comprising a hook for inserting in the electronic device; a pressing member capable of being movable locked and unlocked from the cover; a locking member fastened on the cover and engaged with the pressing member, and an activating member disposed on the cover for activating the pressing portion to unlock from the cover. The locking member includes an inserting portion for inserting into the locking slot to lock the hook in the electronic device.