The present invention provides an image taking main unit that prevents entry of foreign matter and has excellent usability even when an image taking lens unit is not attached thereto. The image taking main unit has a concave mount to which the image taking lens unit with an image taking optical system and an imaging device is removably attached and receives image signals from the image taking lens unit attached thereto to record the image signals therein. The image taking main unit also has a barrier and an electronic device disposed on the barrier. The barrier covers an opening of the mount and retracts into the concave portion of the mount by being pressed by the image taking lens unit when the image taking lens unit is attached to the image taking main unit.