The invention aims at improving the scalability of a storage system using a switch with a small number of ports.A storage system includes a plurality of host connection control units 10 connected to host computers; a plurality of drive control units 12 connected to disk drives 13; and a plurality of 4 by 4 switching units 11 located between each of the host connection control units 10 and each of the drive control units 12, and switching a plurality of paths connecting each host connection control unit 10 and each drive control unit 12, wherein the plurality of 4 by 4 switching units 11 is arranged in multiple stages in the direction of information transmission and the 4 by 4 switching units 11 in each stage are connected so that only two paths are defined from a given host connection control unit 10 from among the host connection control units 10, to every drive control unit 12, and the two paths have no parts in common.