An intermediate adapter includes: a first mount unit having a first mount center point, at which a camera body, with twelve body connector terminals disposed near a camera body mount unit at the camera body, is mounted; a body-side connector terminal holding portion where twelve body-side connector terminals, each connected to one of the twelve body connector terminals and each including a contact area to come into contact with one of the body connector terminals, are disposed; a second mount unit having a second mount center point, at which a camera accessory is to be detachably mounted.