An electronic endoscope apparatus uses an image storage memory capable of storing image data of one or more examinations and records the image data on a recording medium. In response to a redisplay command, it judges whether the image size for a connected electronic scope matches the image size of the data in the image storage memory. If no match is found, the electronic endoscope apparatus changes the clock signal generated by a timing generator to the one suitable for the image size in the image storage memory and redisplays the image data read out of the image storage memory using the clock signal with this frequency on the monitor screen. This makes it possible to redisplay images of a finished examination easily in a constant screen display size.