PURPOSE: To improve the processing efficiency of a CPU and to reduce the burdens of a software and a programmer by providing a data transfer control part.

CONSTITUTION: A data transfer control part 6 is built in a microcomputer and the part 6 is equipped with a transfer time register 61 to show the quantity of a data transfer processing program and transfer data prepared in a microprogram, memory address registers 62 and 63 for data transfer and transfer control register 64 to control the cause, etc., of transfer activation. Accordingly, without saving a flag and program address showing the executing state of the program interrupted by interruption, data can be automatically transferred. Thus, the data can be efficiently transferred and the burden of the software programmer can be reduced.