A prediction method for predicting a computer-resource usage amount with the use of a service call relation to be extracted from a business process definition. A resource allocation method includes, before adding a new business process to the system, steps of calculating the computer-resource predicted usage amount by using a computer-resource usage amount prediction step and of allocating a computer, as a new service execution computer, to a service execution computer whose computer-resource predicted usage amount has exceeded a predetermined value, the computer being different from the service execution computer.