This storage system includes a virtual storage selection unit for selecting a virtual storage unit to be allocated to a virtual server unit according to a virtual storage search policy table for searching the virtual storage unit based on a parameter input by a user when a command is issued for allocating the volume to the virtual server unit, a volume selection unit for selecting the type of volume to be allocated to the virtual storage unit allocated to the virtual server unit with the virtual storage allocation unit according to a volume type search policy table for searching the type of volume based on the parameter, and a volume allocation unit for creating the volume selected with the volume selection unit based on the parameter and allocating the created volume to the virtual storage unit allocated to the virtual server unit with the virtual storage allocation unit.