Abstract: A software rental system that offers commercial software products to client systems on the rental basis over a communication network is disclosed, wherein the commercial software product is installed on the client terminal in the client system. Every software product installed on the client terminal has a first license manager built thereinto. When a software component of the software product that resides on the client terminal is activated and terminated by the user, the first license manger is enabled to intercept the start time and end time, and send this time information, over the communication network, to a second license manager within the appropriate server system that has licensed the user to use the software product. On the server system, the start time and end time information received from the first license manager is analyzed, and the usage fee to be charged to the user is calculated.