An endoscope apparatus comprises an insertion portion having an observation optical system attached onto the distal end portion thereof and having flexibility, a thrust generating portion for generating a thrust by rotation, formed beyond a predetermined length on an outer-peripheral surface of the insertion portion in a longitudinal-axis direction, a rotation device for rotating the thrust generating portion around the longitudinal axis, and a control portion for controlling a rotational speed of the thrust generating portion according to an insertion length of the thrust generating portion inserted in a subject.
