An apparatus includes a switching member which is attached to a main unit of the apparatus; a fixing member which is placed to be movable in a direction along a surface of a supporting portion that is an attaching portion for the switching member, and that contacts with and supports the switching member, which is disposed separately from or integrally with the switching member, and which fixes the switching member; an opening/closing member which has an opening for operating the switching member, and which is openably and closably disposed with respect to the main unit to cover a periphery of the switching member; and a positioning member as defined herein.