The electrochemical thermoelectric coefficient (S_EC =dV/dT; V and T are the redox potential and temperature, respectively) is a significant material parameter, because it enables us to convert thermal energy to electric energy. We demonstrate that a battery-type thermocell, which consists of two kinds of Prussian blue analogues (PBAs) with different S_EC, produces electric energy during heat cycles. The Figure shows heat cycle of battery-type thermocell against cell voltage (V_cell) and temperature (T). The heat cycle consists of four processes: (i) heating from T_L to T_H , (ii) discharge at T_H, (iii) cooling from T_H to T_L, and (vi) discharge at T_L. The heating and cooling processes are performed without current (I = 0) The device produces electric energy of 2.3 meV/PBA par a heat cycle between 295 K (= T_L) and 323 K (= T_H). The thermal efficiency (= 1.0 %), which is evaluated with use of the heat capacity (C = 4.16 meV/K) of ideal Na₂Co[Fe(CN)₆], reaches 11 % of the Carnot efficiency (= 8.7 %). Our battery-type thermocell is a promising thermoelectric device that harvests waste heat near the room temperature.