PURPOSE: To accelerate instruction processing time by setting instruction execution time when an instruction word in a program memory is a two-word instruction equal to the instruction execution time for a one-word instruction in a program controller.

CONSTITUTION: The program controller is equipped with a first program memory 15 which stores instruction data of even(odd)-numbered address of a program and a second program memory 16 which stores instruction data of odd(even)- numbered address of the program, and reads out and executes the two words of the two-word instruction simultaneously by providing a means addressing the first and second program memory exclusively by a program counter 11 and an address generation circuit 12 always generating an address incremented by one than the one indicated by the program counter 11, and switching the incremental value of the program counter 11 to 1 or 2 by the decode output of an instruction decoder circuit 19.