An electronic endoscope system (1) which includes an endoscope (2) having an insertion portion (5) rotatable with respect to an operation portion (6) and electronically picks up an image of a subject, the electronic endoscope system includes: a physical quantity generation portion (13) provided at the insertion portion (5) and configured to generate a physical quantity which changes depending on a rotation angle of the insertion portion (5) with respect to the operation portion (6) a detection portion (14) provided at the operation portion (6) and configured to detect the physical quantity generated by the physical quantity generation portion (13) a rotation angle calculation portion (15) configured to calculate the rotation angle of the insertion portion (5) based on the physical quantity detected by the detection portion (14) and a display portion (4) configured to display an image of the subject, and perform a display indicating the rotation angle of the insertion portion (5) with respect to the operation portion (6) based on the calculated rotation angle.
