A fog-resistant structure and a protective device for eyes is configured such that a transparent conductive film is formed on one surface of a lens or shield, a linear electrode is provided on upper and lower portions of the surface of the lens or shield so that each of a central region and opposite side regions of the lens or shield has substantially equal spacing between the upper and lower linear electrodes. Thus each region of the lens or shield has no difference in temperature without regulating power supplied to the transparent conductive film, thereby eliminating wasted power consumption and allowing even a structure using a battery as the power supply to have much longer available time.