Disclosed is a disk storage apparatus to control writing to a storage medium having a storage area to which a first address space is allocated and whose transfer rate spatially changes, including a command reception section and control section. The command reception section receives a write command from a host apparatus and containing an address of the first address space. The control section performs control to divide the storage area into zones, pre-define a second address space where blocks are successively allocated to the zones from a beginning address of the first address space, replace, for each of the write commands received by the command reception, an address of the first address space contained therein with an address of the second address space, select one of the zones as a write target zone by cyclical changing, and perform a writing process to the storage medium for each selected zone.