PURPOSE: To flexibly respond the increase of the quantity of a traffic in a digital exchange by providing one or plural second processors assisting the processing performed by respective processors belonging to the first processor groups processing load in a dispersion in accordance with the increase of the quantity of the processing.

CONSTITUTION: When the quantity of the traffic of respective networks N1∼N4 can be processed only by all function processors P1∼P4, assisting processors P5 and P6 stand by in preparation of the generation of a high traffic and engage in the processing except for the traffic processing in accordance with the necessity. When the traffic is increased and the quantity required for the processing exceeds a processing capacity, the quantity of the processing of a local processor LP part is increased and the quantity of the processing of a main processor MP part is decreased. The processor P5 assists the processing in the main processor MP part of the all function processor in which the above mentioned processing rate is changed. When the quantity of the traffic is further increased and only the processor P5 cannot assist the all function processors P1∼P4, the processor P6 starts to assist the processor P5.