An operation management system for managing the operation of a managed software product. When a management target function is executed, reference is made to a battery value and, if the value is zero or greater, the function is allowed to be executed. The battery value is decremented as the function is executed. A charge value is supplied on a charge disk, such as a floppy disk, to allow the user to increase the battery value and to extend the usage period of the managed software product. The charge value may be supplied over a communication line.