We fabricated a hybrid power source device with three electrodes of which one was a LiPF6-doped polyaniline (PAn) electrode playing the roles of both the positive electrode of a lithium secondary battery and an electrode of a redox supercapacitor. As a consequence, the shared electrode acts as a positive electrode or a positive terminal of a hybrid power source. The negative terminal was connected between a lithium metal electrode and another LiPF6-doped PAn electrode. After characterizing and comparing this hybrid power source with a single lithium secondary battery, its discharge performance was superior to that of a single lithium secondary battery when adopting the sheet-type PAn-LiPF6 electrodes and the porous separator as an electrolyte medium. In this case, the hybrid power source was shown to be advantageous in the high pulse mode of discharge.