Camera body, imaging unit mounted/removed on/from the camera body and imaging apparatus

A camera body formed with a concave portion on/from which an imaging unit is attachably and detachably mounted/removed, the imaging unit being provided in a rectangular case with an optical system, an imaging device and a unit side connector portion, and a body side connector portion which is connectable to the unit side connector portion, the camera body being integrated with the imaging unit and used as an imaging apparatus for photographing the subject,

• wherein the concave portion includes three wall portions of a back wall portion which a back face of the case faces, a side wall portion which a left side face of the case faces, and an upper wall portion which an upper face of the case faces, when the imaging unit is mounted on the concave portion when viewed from the subject side in a direction of an optical axis of the optical system,
• wherein the camera body includes a locking member for locking the imaging unit in cooperation with a locking member to be locked formed in the imaging unit,
• wherein an unlocking operation member for unlocking a lock of the camera body and the imaging unit by means of the locking member is disposed in an intersection portion of the side wall portion and the upper wall portion, and
• wherein at least three wall portions which composes the concave portion are opened.