A virtual machine is efficiently constructed, and a constructing time is reduced. Other than a target virtual machine which is a target for setting parameters, a setting purpose virtual machine is provided, and without starting the target virtual machine, a host side virtual machine setting unit of a host obtains a target virtual machine setting parameter file, and makes a storage area for setting parameters of the target virtual machine (a target virtual machine data) accessible from the setting purpose virtual machine, and a guest side virtual machine setting unit sets the parameters of the target virtual machine without starting the target virtual machine by obtaining the target virtual machine setting parameter file from the host side virtual machine setting unit, and writing the setting parameters in the storage area for setting the parameters of the target virtual machine (the target virtual machine data) which has been made accessible.