It is an object to provide a computer system, a license management method, and a program capable of effectively using owned licenses and improving the convenience. A computer system that manages licenses of an application acquires a number of owned licenses, calculates a number of unused licenses which are not currently used, determines a number of rentable licenses from the calculated number of unused licenses, and provides the determined rentable licenses. Further, the computer system stores the number of rentable licenses and a rental period of the rentable licenses in association with each other, and provides the rentable licenses during the rental period. Furthermore, the computer system provides a minimum number of licenses among numbers of rentable licenses in the rental period.