Provided are an electrode unit and a method for manufacturing the electrode unit. According to the present invention, after the electrode unit is manufactured by using heat, bending of the electrode unit occurring by cooling the electrode unit may be eliminated or minimized. To achieve the aforementioned object, in the method for manufacturing the electrode unit according to an embodiment of the present invention, stress applied to the inside of each of the positive electrode collector and the negative electrode collector is calculated to reflect the calculated results, thereby selecting the positive electrode collector and the negative electrode collector.