A portable electronic apparatus has a bottom case and a cover. The bottom case has a bottom wall and an opening that opposes the bottom wall. A printed circuit board is disposed in the bottom case. The cover has a keyboard unit and is removably attached to the case so as to cover the opening portion. The keyboard unit has a main body having an under side, a shielding plate and a film member. The shielding plate is fixed to the under side and shields the electromagnetic noise produced by the keyboard unit. The film member has a circuit pattern disposed thereon and is disposed between the under side and the shielding plate. The apparatus is able to secure the cover to the case. The cover may have a fixing portion, and the apparatus may have screws for securing the fixing portion. A keyboard frame surrounds the keyboard unit and is detachably connected to the bottom case and the cover. Finally, the keyboard unit may be detachable from the cover.