Abstract: A control apparatus for a rotation type magnetic storage device such as a magnetic disc device in which each of record tracks is composed of plural sectors, is disclosed. The apparatus comprises a memory for storing control information of address and the like of the sector to be accessed on a rotating recording medium and comparator means for comparing successively the control information read out from the sector of the rotating recording medium with the control information read out from the memory. In accordance with the output signal from the comparator, the sector of the rotating medium to be accessed is detected. The rotation type magnetic storage device having different sector formats can be controlled by altering correspondingly the control information stored in said memory.