PURPOSE: To array data in desired format by adding the desired data format and a digit-by-digit shift value to data to be outputted to an external device, and controlling a shifting circuit and an output buffer associatively with each other.

CONSTITUTION: Data on a signal line 11 is inputted to a selector 1, whose output is inputted to the shifting circuit 2, the output of which is inputted to an output buffer 3. The shift amount supplied to the circuit 2 is stored in a shift value register 5, whose output is supplied to the circuit 2 and also supplied to a loading control circuit 6 which generates the loading signal of the output buffer 3. The output of a circuit 6 is inputted as the loading signal to the buffer 3. The output of a mode register 4 which holds a mode determination signal is supplied to a selector 1. Then when the output of the register 4 is 0, an unpacking mode is entered. Further, a signal P which indicates whether the high-order bits or low- order bits of the input data are to be unpacked is inputted as an input switching signal to the selector 1.