A secondary battery reuse method for a secondary battery provided with a secondary battery pack having a plurality of modules, each module being formed of a secondary battery cell or a secondary battery stack containing a plurality of secondary battery cells, the method comprising: measuring a resistance and a capacity of each module (SP12, SP22); comparing the measured resistance of each module with a preset first threshold value; comparing the measured capacity of each module with a preset second threshold value; determining a module to be a reusable module when its measured resistance is less than or equal to the first threshold value and its measured capacity is greater than or equal to the second threshold value (SP13, SP14, SP15); determining a module to be a non-reusable module when its measured resistance is larger than the first threshold value or its measured capacity is less than the second threshold value (SP13, SP14, SP16); and constructing a new secondary battery pack by combining the reusable module with an unused module or a module from a used secondary battery pack which is equivalent to the unused module, and placing a secondary battery provided with this new secondary battery pack in use (SP24, SP25), characterized in that the first threshold value and the second threshold value are set using as a condition that a degree of deterioration in the resistance and a degree of deterioration in the capacity of a module in a secondary battery pack in a used secondary battery are respectively equal to a degree of deterioration in the resistance and a degree of deterioration in the capacity of a module in a secondary battery pack prior to use, wherein said degree of deterioration in said resistance is a rate of increase in said resistance per a fixed time interval or a fixed travel distance, and said degree of deterioration in said capacity is a rate of decline in said capacity per a fixed time interval or a fixed travel distance. measuring a resistance and a capacity of each module (SP12, SP22); comparing the measured resistance of each module with a preset first threshold value; comparing the measured capacity of each module with a preset second threshold value; determining a module to be a reusable module when its measured resistance is less than or equal to the first threshold value and its measured capacity is greater than or equal to the second threshold value (SP13, SP14, SP15); determining a module to be a non-reusable module when its measured resistance is larger than the first threshold value or its measured capacity is less than the second threshold value (SP13, SP14, SP16); and constructing a new secondary battery pack by combining the reusable module with an unused module or a module from a used secondary battery pack which is equivalent to the unused module, and placing a secondary battery provided with this new secondary battery pack in use (SP24, SP25), characterized in that the first threshold value and the second threshold value are set using as a condition that a degree of deterioration in the resistance and a degree of deterioration in the capacity of a module in a secondary battery pack in a used secondary battery are respectively equal to a degree of deterioration in the resistance and a degree of deterioration in the capacity of a module in a secondary battery pack prior to use, wherein said degree of deterioration in said resistance is a rate of increase in said resistance per a fixed time interval or a fixed travel distance, and said degree of deterioration in said capacity is a rate of decline in said capacity per a fixed time interval or a fixed travel distance.