A method for producing a lithium ion secondary battery having an electrode assembly formed of superimposed positive and negative electrode sheets, with a separator sheet being interposed therebetween, the method comprising: selecting a positive electrode sheet, negative electrode sheet, and separator sheet; constructing an electrode assembly by superimposing the selected positive electrode sheet, negative electrode sheet, and separator sheet; and housing in a battery case the electrode assembly along with an electrolyte solution, wherein at least one of the positive electrode sheet and negative electrode sheet is selected such that it satisfies the relationship 0.8 < a/b < 1.5 when, in tests under conditions and below: Condition a high rate loading-unloading cycle is repeated n times (n ≥ 3), the cycle including a step of applying a load at a rate of A [mN/second] until a given load F1 [mN] is reached, and a step of removing the load at the rate of A [mN/second] until a given load F2 [mN] is reached, and Condition a low rate loading-unloading cycle is repeated n times (n ≥ 3), the cycle including a step of applying a load at a rate of B [mN/second] (B ≤ 0.2A) until a given load F1 [mN] is reached, and a step of removing the load at the rate of B [mN/second] until a given load F2 [mN] is reached, a value of 100% is defined as the thickness of the sheets before starting the test, with the thickness of the sheets being the vertical axis and the number of loading-unloading cycles being the horizontal axis, the changes in the thickness of the sheets from cycles 1 to n under load F1 and the changes in the thickness of the sheets from cycles 1 to n under load F2 are plotted and extrapolated on a graph; the thickness of the sheets and the number of loading-unloading cycles corresponding to convergence points of these distributions are determined; slopes of the straight lines connecting the thickness of the sheets before starting the tests to the convergence points are determined; and when a represents the slope of the straight line in the test conducted under condition, and b represents the slope of the straight line in the test conducted under condition. selecting a positive electrode sheet, negative electrode sheet, and separator sheet; constructing an electrode assembly by superimposing the selected positive electrode sheet, negative electrode sheet, and separator sheet; and housing in a battery case the electrode assembly along with an electrolyte solution, wherein at least one of the positive electrode sheet and negative electrode sheet is selected such that it satisfies the relationship 0.8 < a/b < 1.5 when, in tests under conditions and below: Condition a high rate loading-unloading cycle is repeated n times (n ≥ 3), the cycle including a step of applying a load at a rate of A [mN/second] until a given load F1 [mN] is reached, and a step of removing the load at the rate of A [mN/second] until a given load F2 [mN] is reached, and Condition a low rate loading-unloading cycle is repeated n times (n ≥ 3), the cycle including a step of applying a load at a rate of B [mN/second] (B ≤ 0.2A) until a given load F1 [mN] is reached, and a step of removing the load at the rate of B [mN/second] until a given load F2 [mN] is reached, Condition a high rate loading-unloading cycle is repeated n times (n ≥ 3), the cycle including a step of applying a load at a rate of A [mN/second] until a given load F1 [mN] is reached, and a step of removing the load at the rate of A [mN/second] until a given load F2 [mN] is reached, and Condition a low rate loading-unloading cycle is repeated n times (n ≥ 3), the cycle including a step of applying a load at a rate of B [mN/second] (B ≤ 0.2A) until a given load F1 [mN] is reached, and a step of removing the load at the rate of B [mN/second] until a given load F2 [mN] is reached, a value of 100% is defined as the thickness of the sheets before starting the test, with the thickness of the sheets being the vertical axis and the number of loading-unloading cycles being the horizontal axis, the changes in the thickness of the sheets from cycles 1 to n under load F1 and the changes in the thickness of the sheets from cycles 1 to n under load F2 are plotted and extrapolated on a graph; the thickness of the sheets and the number of loading-unloading cycles corresponding to convergence points of these distributions are determined; slopes of the straight lines connecting the thickness of the sheets before starting the tests to the convergence points are determined; and when a represents the slope of the straight line in the test conducted under condition, and b represents the slope of the straight line in the test conducted under condition.