Disclosed herein is a reference electrode including an electrolyte containing an optically-active material, including: an electrode body provided at an end thereof with an electrolyte separation membrane and charged therein with an optically-active material and an electrolyte solution; an inner electrode disposed in the electrode body to be immersed in the electrolyte solution; and an absorbance measurement probe for transmitting light to the electrolyte solution and collecting reflected light waves, which is disposed in the electrode body to be immersed in the electrolyte solution. Since the concentration of an electrode reaction material, such as Cl−, in the electrolyte is calculated using the absorbance of the electrolyte solution containing the optically-active material, the change in potential of the reference electrode can be properly corrected even when the reference electrode is exposed to a test environment for a long period of time and thus the concentration of the electrolyte changes. Thus, the functions of the reference electrode can be maintained for a long period of time, thereby rapidly monitoring the abnormal states caused by damage to the reference electrode.