A camera body to which an image pickup unit including an optical system, an image pickup device, and an image-pickup-unit connector is detachably attached, includes a recess to which the image pickup unit is freely detachably attached and which includes a back wall, an upper wall, and a side wall to be opened on a lower side, a lateral side, and a front side of the camera body. The back wall faces a rear of the image pickup unit, the upper wall is located on an upper side of the camera body in a normal use state. The camera body includes a locking mechanism to control a movement of the image pickup unit placed in the recess in a direction in which the image pickup unit moves away from the side wall, a first unlocking mechanism provided to be exposed from the camera body and configured to unlock a locked state made by the locking mechanism in response to an unlocking manipulation, and a second unlocking mechanism provided to be enclosed inside the camera body and configured to unlock the locked state made by the locking mechanism in response to an unlocking manipulation.