A storage device in which the MR-IOV is applied to an internal network of a storage controller. Data path failover can be executed in the storage device. The internal network of the storage controller is configured to enable the access of a virtual function (VF) “VF 0:0, 1” of each endpoint device (ED0-ED2) from a root port RP0. Likewise, “VF 1:0, 1” of each endpoint device can be accessed from a root port RP1. In a first data path from the RP0 to ED0 in a normal state, “VF 0:0, 1” and “MVF 0, 0” are connected by VF mapping. When a failure occurs on the first data path, the MR-PCIM executes the VF migration, whereby in the second data path from the RP1 to ED0,“VF 1:0, 1” and “MVF 0, 0” are connected by VF mapping. As a result, failover to the second data path is realized.