PURPOSE: To enable a dispatching mechanism to decide the using right of a CPU at a high speed by excluding a group of control blocks having the same priority and kept under the control of a pseudo control block out of the queue searching subjects in case said group of control blocks needs no using right of the CPU for the time being and discontinues their execution.

CONSTITUTION: When a group 130 of control blocks having the same executing priority discontinues their execution, a skip setting means 112 sets a skip mode at a 1st pseudo control block that is connected to the preceding state of the group 130. Thus, a queue searching action is immediately skipped to a 2nd pseudo control block to start a queue searching action of the next control block 120 after bypassing the group 130. Furthermore, the means 112 sets a search mode at the 1st pseudo control block as long as the group 130 having the same priority is kept under an execution enable state requiring the using right of the CPU.