An electronic endoscope has a video-scope with an image sensor, a light source, a signal reading processor, a shading member, a driver, and a driving controller. The signal reading processor alternately reads odd-line image-pixel signals and even-line image-pixel signals over one-frame reading interval, when forming a still image on the basis of one frame worth of image-pixel signals generated by a one-time exposure. The shading member blocks the illuminating light. The driver selectively arranges the shading member at a non-shading position that enable the illuminating light to pass and at a shading position that blocks the light. The driving controller controls the driver by a sequence of pulse signals so as to position the shading member at the shading position for a shading-interval in the one-frame reading interval, and so as to position the shading member at the non-shading position for a remaining reading-interval.