In a business system which allocates a request for one business application to one or more of the computer resources executing such business application, the computer resources are accommodated among the plurality of the business systems so that the load covered by each of the business systems is averaged out. The arbitration apparatus for resource allocation 101 calculates a margin rate for each business system by measuring load for respective business systems, and by calculating a ratio of the measured load and the allowable execution amount allowable under current constitution. When a computer resource 1241 which is not allocated to business system is found, this computer resource is allocated to the business system indicating low margin rate while if such computer resource 1241 is not found, the computer resource 1241 is reallocated by being released from the business system having high margin rate.