PURPOSE: To save a time required for decoding in a decoder, by holding a control signal which controls a data selector, and performing the replacement of a high-order word and a low-order word and code expansion by the control signal.

CONSTITUTION: A data time read out from a memory device 2 is stored in a data register 10 with a timing of t2, and out of the control signals decoded by the decoder 13 with the timing of the same time t2, a signal which controls the data selector 11 is also stored in a control register 14. The data stored in the data register 10 is outputted to an internal bus 22 via the data selector 11, and the data selector 11 is controlled by the code of the control signal sent from the control register via a control signal line 26. At this time, since the control signal is stored in the control register 14, the time for the decoding can be saved.