An electronic endoscope using a solid-state image pickup device has a filter arranged in the foreground of the solid-state image pickup device within the body of the endoscope for removing lights having wavelengths not related to observation in order to effectively eliminate those light components which are not required for the observation from among those lights incident to the solid-state image pickup device. As such a filter, either a lens component constituting the objective lens or an illuminating lens can be used.