An imaging unit to be inserted into a camera body from a predetermined direction, thus to constitute a digital camera in combination with the camera body, is provided. The imaging unit is provided with an image pickup unit including an imaging device that obtains an object image, an imaging device driver that drives the imaging device, an image processor that processes an output signal of the imaging device; a casing for accommodating the image pickup unit, the imaging device driver and the image processor, and a lid attached to the casing so as to slide between a closed position where the lid covers a receiving surface of the image pickup unit, and an open position where the lid does not cover the receiving surface of the image pickup unit. In this structure, the lid is moved to the open position by a force exerted for inserting the imaging unit into the camera body.