PURPOSE: To simplify the constitution of an inter-multi-party specific processing execution means by providing the inter-multi-party specific processing execution means executing only the processing specific to the service relating to three subscribers or over.

CONSTITUTION: When an inter-multi-party specific processing execution means 200 executes a service relating to three subscribers or over, the means 200 requests the processing between the two subscribers in the three subscribers or over to an inter-two-party call processing execution means 100 to execute the processing specific to the service relating to the three subscribers or over. Moreover, the means 200 requests the processing among the three parties to manage the means 100. Thus, in the case of executing the service relating to the three subscribers or over, a stored program control exchange requests the processing between the two subscribers for the means 100 and the means 200 to execute only the processing specific to the service relating to the three subscribers or over is provided and the constitution of the means 200 is simplified.