PURPOSE: To reduce the memory capacity used for task management and to quickly perform the operation processing of management information with respect to a real time OS of an 8-bit microprocessor.

CONSTITUTION: A task control block(TCB) arranging means 2 is provided which fixedly arranges first, second, and third TCBs 4, 5, and 6 in the area of management addresses 0 to 255 of a memory 3. Lower 8 bits of arrangement address information are preserved by task connection pointers indicating connections of tasks in TCBs 4, 5, and 6 and a connection queue 7 to indicate the other party of connection. By this task connection management, a multitask controller of high speed where the used memory capacity is small is obtained.