A technology for rescuing an object when a failure occurs in a redundant system. In a synchronization memory, an instance of an object, which includes the virtual function discrimination information for discriminating a memory area where a virtual function corresponding to the object is stored, the class information for discriminating a class corresponding to the object, and the object data to be used for the processing of the object, is stored according to the order of the processing. In a function memory, plural kinds of virtual functions generated for each process to be carried out by the object are stored. When the object of a new active server reproduces the process, the class corresponding to this object is discriminated using the class information, and the virtual function discrimination information of this object is rewritten.