PURPOSE: To efficiently realize the dynamic and exclusive control of plural kinds of process with a simple hardware and a small overhead.

CONSTITUTION: When a data packet holding an instruction code which issues a TEST & SET instruction arrives at an instruction executing part 26, the instruction executing part 26 reads the semaphore-flag of a semaphore-flag storage part 34. When the read-out semaphore-flag is '0', the semaphore-flag is set to be '1' and also it is permitted that an instruction node number held by the data packet is updated into the new number. Then a required processing is executed. When the read-out semaphore-flag is '1', it is not permitted that the instruction node number held by the data packet is updated into the new number and the data packet is permitted to stand-by while circulating on a circulation pipe line 14 till the semaphore-flag becomes '0'. A semaphore-reset signal (c) and the semaphore-reset signal (d) can be used for resetting the semaphore-flag for '0'.