An object of the present invention is to suppress a variation in virtual machine startup times when multiple virtual machines are started in a computer system having multiple virtual machine providing servers. Execution server distribution unit 13 references a virtual machine status management table 32, which stores the status of virtual machine providing servers 90 in which virtual machines 91 are operating and the status of the virtual machines 91, and determines the positions of virtual machines in such a way that virtual machines, which execute specific processing (virtual machine startup, and so on) registered in a distributed processing specification table 31, are distributed. Operation server consolidation unit 16 references the virtual machine status management table 32 and determines the arrangement of the virtual machines 91 in such a way that virtual machines, which have executed the specific processing and are performing usual operations, are consolidated (FIG. 1).