To provide an access controlling method and device capable of reducing the competition of accesses generated between plural data processors sharing a storage part consisting of plural storage devices.

When a data processor X requests a reading request of a long unit (provided that an even address A2 is a head), data are collectively read out from both storage devices A, B as shown in the timing of a clock CK2 e.g. the data RD2 read out from the storage device A are supplied to a data bus DX and the data RD3 read out from the storage device B are stored in an X side reading work register. At the timing of a succeeding clock CK3, the data RD3 stored in the work register are read out first and supplied to the data bus DX. Since accesses to the storage devices A, B are collectively carried out in the case of a long access and the number of accesses to the storage devices A, B is reduced, the possibility of occurrence of competition of accesses can be reduced.