There is provided an endoscope apparatus which enables both of a 2-D observation and a 3-D observation favorably. An endoscope apparatus having a function of switching between the 2-D observation for a planar view and the 3-D observation for a stereoscopic view, includes an image processor which reduces a distortion of an image pickup optical system at the time of the 3-D observation, and the image processor carries out image processing that satisfies the following conditional expression (1): 0.1 <； B / A <； 0.8 , as well as A <； 0 where, A denotes a distortion at the maximum image height at the time of the 2-D observation, and B denotes a distortion at the maximum image height at the time of the 3-D observation.
