PURPOSE: To easily execute the addition of a new service and the addition and change of the function of an existing service by executing plural service features stored in a data base corresponding to the described contents of an execution order table.

CONSTITUTION: The execution order table 102 and a service feature group 103 are stored in the data base 101. The service feature group 103 is constituted of the service features 1031-103n provided with versatility for finely turning the functions required for the respective services in an intelligent network to parts and the execution order of the respective service features 1031-103n and input/output parameters required for the execution, etc., are described in the execution order table 102. Then, corresponding to an order registered in the execution order table, a controller combines the service features and lets a main function 104 execute the service. Thus, the addition of the new service and the addition and change of the function of the existing service are performed only by changing the stored contents of the data base.