A drop in the access performance to a source volume is prevented by executing various control methods according to the snapshot usage method. A storage apparatus comprises one or more storage devices which provide storage areas; and a controller which creates a logical volume in the storage area provided by the one or more storage devices, and which reads and writes data from/to the logical volume according to a request from a host, wherein the controller acquires one or more snapshots which are data images at certain time points of the logical volume, wherein the controller determines whether the logical volume is subject to abrupt load fluctuations on the basis of performance information of the logical volume and the snapshots, and wherein, if the logical volume is subject to abrupt load fluctuations, the controller executes predetermined control processing according to usage cases of the snapshots.