PROBLEM TO BE SOLVED: To reduce the diameter of an insert part in simple and small-sized constitution, and to control lens position with high accuracy in an electronic endoscope apparatus adapted to drive a lens using a torque wire.SOLUTION: This lens position control device rotates a motor toward the Tele side to a point P1 where the rotating speed of the motor is lower than a threshold in the power-on state. After that, it rotates the motor toward the Wide side to a point P2 where the rotating speed of the motor is lower than a threshold. In the rotation from the point P1 to the point P2, the rotation of the motor is counted to thereby detect the amount A1 of rotation of the motor to a rotatable range. Supposing that the center of the mechanical movable range A3 of a cam ring is aligned with the center of the rotatable range of the motor, a section A2 used by the motor under the lens position control is determined from the rotational frequency corresponding to the mechanical movable range A3 of the cam ring obtained in design. The end point P3 at the Wide side of the section A2 is taken as an origin in the lens position control processing. In the lens position control processing, when the motor reaches the origin position, again the origin position is adjusted.
