PURPOSE: To prevent the selecting efficiency error caused by the priority setting characteristics by providing a control table exclusive for the registration/ selection of data and attaining the selection of data with the optimum efficiency.

CONSTITUTION: When the data 13 is registered, a register inlet 11 is first decided in response to a group to which the produced data 13 belongs. Then the list elements corresponding to the data 13 are registered into a list set ahead of a selection inlet 12. At the registration of list elements, the elements are sorted and registered according to the priority of the data 13 so that the data 13 having the highest priority is set at the head of the list. Thus it is possible to assure the optimum selection efficiency that is always fixed regardless of the priority and the order set among groups.