An imaging unit comprising: an imaging device for transmitting image data to an external display device; and an installation portion that is attachable to and detachable from the display device, wherein the imaging device and the installation portion are either formed as separate devices, whereby the installation portion is attachable to and detachable from the imaging device, or as an integrated device, wherein said installation portion, when attached to or formed as an integrated device with the imaging device, is arranged on top of the rear surface of the imaging device and represents the rear part of the imaging unit, wherein the imaging device includes a communication part for transmitting image data to the display device; an outer barrel; and an imaging element, wherein the installation portion includes a slider (23, 31) that is slidable with respect to the outer barrel; a first attached body that is connected to the slider; a second attached body that is configured that a gap between the first attached body and the second attached body can be changed, wherein the display device can be grasped by the first attached body and the second attached body; and a biasing member (30, 37) for biasing the first attached body to resist enlargement of the gap between the first attached body and the second attached body and to hold the display device in the gap between the first attached body and the second attached body. an imaging device for transmitting image data to an external display device; and an installation portion that is attachable to and detachable from the display device, wherein the imaging device and the installation portion are either formed as separate devices, whereby the installation portion is attachable to and detachable from the imaging device, or as an integrated device, wherein said installation portion, when attached to or formed as an integrated device with the imaging device, is arranged on top of the rear surface of the imaging device and represents the rear part of the imaging unit, wherein the imaging device includes a communication part for transmitting image data to the display device; an outer barrel; and an imaging element, a communication part for transmitting image data to the display device; an outer barrel; and an imaging element, wherein the installation portion includes a slider (23, 31) that is slidable with respect to the outer barrel; a first attached body that is connected to the slider; a second attached body that is configured that a gap between the first attached body and the second attached body can be changed, wherein the display device can be grasped by the first attached body and the second attached body; and a biasing member (30, 37) for biasing the first attached body to resist enlargement of the gap between the first attached body and the second attached body and to hold the display device in the gap between the first attached body and the second attached body. a slider (23, 31) that is slidable with respect to the outer barrel; a first attached body that is connected to the slider; a second attached body that is configured that a gap between the first attached body and the second attached body can be changed, wherein the display device can be grasped by the first attached body and the second attached body; and a biasing member (30, 37) for biasing the first attached body to resist enlargement of the gap between the first attached body and the second attached body and to hold the display device in the gap between the first attached body and the second attached body.