A high availability system includes a first server computer for a first virtual computer and a first hypervisor and a second server computer for a second virtual computer and a second hypervisor. The first virtual computer executes a processing and the second virtual computer executes the processing behind from the first virtual computer. Information associated with an event is transmitted. The event provides an input to the first virtual computer. In the second hypervisor, a control unit performs, control based on the information to match the execution state of the second virtual computer and that of the first virtual computer, and control associated with the information, when the event associated with the information is predetermined one of an I/O completion interrupt from the first virtual storage and an interrupt handler call corresponding to the interrupt, after the interrupt from the second virtual storage corresponding to the interrupt is caught.