An endoscope system includes: an insertion portion a front view observation window configured to acquire a first object image a first image pickup device configured to generate a first image pickup signal a side view observation window configured to acquire a second object image a second image pickup device configured to generate a second image pickup signal an inclination angle detection portion configured to detect a rotation around an axis and generate inclination information and a video processor configured to generate an image signal representing a state that an image represented by the second image pickup signal is made to revolve following the rotation and arranged with respect to an image represented by the first image pickup signal, based on the inclination information, the first image pickup signal and the second image pickup signal, and output the image signal to a display portion configured to display the image.
