PROBLEM TO BE SOLVED: To provide a zoom lens built-in electronic endoscope apparatus capable of having built-in motor and speed reducing mechanism without increasing a diameter of an endoscope.SOLUTION: An electronic endoscope apparatus includes: a cam member connected to a lens which transfers along an optical axis of an optical system provided at the preceding stage of the imaging element a cam shaft 111 which allows the lens to transfer along the optical axis via the cam member a gear section 125c which allows the cam shaft 111 to be rotated by integrally connected to an end of the cam shaft 111 and revolving driven a motor 51 arranged on the cam shaft 111 a gear support shaft 126 provided in parallel in an output shaft 51a of the motor 51 and the optical axis and deceleration gear mechanisms 52 provided between the output shaft 51a of the motor 51 and the gear support shaft 126, and between the gear support shaft 126 and the gear section 125c, respectively.
