Each CM retains a function management table in which entry information indicating which function is operating in which CM for what period is registered. Every time a command is executed in a function processing unit on the basis of an instruction from a GUI, components of a CM perform control, communicating registered pieces of content in a function management table to corresponding components of another CM for synchronization among the CMs. Regardless of which of a plurality of CMs in a storage apparatus is a master, processing can be executed in any CM from any GUI without inconsistency in the processing between the CMs.