Polyamides (DTA-I, DTA-II, and DTA-III) containing cyclic disulfide structure were prepared by condensation between 1,2-dithiane-3,6-dicarboxylic acid (DTA) and alkyl diamine, NH2–(CH2) n –NH2 (DTA-I; n=4, DTA-II; n=6, DTA-III; n=8) and their application to positive active material for lithium secondary batteries was investigated. Cyclic voltammetry (CV) measurements under slow sweep rate (0.5mVs−1) with a carbon paste electrode containing the polyamide (DTA-I, DTA-II, or DTA-III) were performed. The results indicated that the polyamides were electroactive in the organic electrolyte solution (propylene carbonate (PC)-1,2-dimethoxyethane (DME), 1:1 by volume containing lithium salt, such as LiClO4). The responses based on the redox of the disulfide bonds in the polyamide were observed. Test cells, Li/PC-DME (1:1. by volume) with 1moldm−3 LiClO4/the polyamide cathode, were constructed and their performance was tested under constant current charge/discharge condition. The average capacity of the test cells with the DTA-III cathode was 64.3Ahkg−1 of cathode (135Whkg−1 of cathode, capacity (Ahkg−1) of the cathode×average cell voltage (2.10V)). Performance of the cell with linear polyamide containing disulfide bond (–CO–(CH2)2–S–S–(CH2)2–CONH–(CH2)8–NH–, GTA-III) was also investigated and the average capacity was 56.8Ahkg−1 of cathode (100Whkg−1 of cathode, capacity (Ahkg−1) of the cathode×average cell voltage (1.76V)). Cycle efficiency of the test cell with the DTA-III cathode was higher than that with the GTA-III cathode.