The endoscope apparatus comprises an endoscope which has an imaging element and a monitor which displays an image imaged by the imaging element. The endoscope is provided with an internal insertion portion which is movably arrangeable inside a body cavity, and an operation unit for changing the position of the internal insertion portion and which is arrangeable outside the body. The internal insertion portion and the operation unit are arranged ON a common axis so as to interpose a body wall therebetween.