To provide a new electrocardiogram analyzing method with higher precision than heretofore by revising a method for determining a treadmill exercise test, which is low in a diagnostic precision conventionally.

(1): The change of an ST level in an electrocardiogram during a treadmill exercise test is measured every 15 seconds. (2): The numerical value of (1) is plotted to a coordinate where time passage is defined as an X-axis and the ST level is as a Y-axis. (3): The fifth point before the end of the test from the end of the test and the fifth point after the end of the test from the end of the test are respectively connected with a line on the plot of (2), so as to define an angle made with the X-axis as θE, and to define an angle made with the Y-axis as θR. The acquired numerical values of θE and θR are multiplied and a numerical value obtained by multiplication is given the name of Bi-Angle Score. When the numerical value of Bi-Angle Score is not less than 1,500, positivity is diagnosed in myocardial ischemia.