A keyboard device according to one embodiment includes: a box-shape body, comprising a first side-wall and a second side-wall arranged opposite to and is pivotably openable relative to the first side-wall; a support assembly, configured to be connected detachably to the first side-wall of the box-shape body such that the box-shape body is adapted to support the electronic apparatus; and a flexible membrane keyboard which is connected with an internal surface of the second side-wall of the box-shape body and switchable between an unfolded condition in which the flexible membrane keyboard functions as a keyboard of the electronic apparatus and a folded condition in which the flexible membrane keyboard is received within the box-shape body. The keyboard device of the embodiments of the disclosure may function as both a keyboard for the electronic device and a support, and is provided with a limited size so as to facilitate portability thereof.