A personal digital assistant 1 composed of a main body 2 formed with an operation section 212; a cover body 3 which is freely attached and slides parallel to the operating section 212 from a position overlapped on the operation section side of the main body 2; and an energization spring 45 formed in the cover body 3 which applies force along a direction which maintains an opened state in an opened position where the cover body 3 has been made to slide from the main body 2. Accordingly, a sliding type personal digital assistant can be stabilized in a closed position and/or an opened position and prevent opening or closing in a midway through position.