An opening/closing mechanism enabling a first housing and a second housing to open to a so-called fully flat state includes a fixed plate that is fixed to a first housing, a moving plate that is fixed to a second housing, an intermediate member that is slidably coupled to the fixed plate by way of a first slide mechanism, a slide member that is slidably coupled to the intermediate member by way of a second slide mechanism, and a raising/lowering mechanism that raises/lowers the moving plate relative to the slide member.