An operator selecting apparatus adapted to for each communication device in a group, a home operator out of a plurality of candidate operators, wherein each candidate operator has a billing system regarding a service as a home operator and wherein the billing system of at least one of the candidate operators is configured to provide a discount in accordance with an increase of communication devices in the group for which the candidate operator is selected, characterized in that the operator selecting apparatus comprising: a receiving unit (201 for receiving group information that defines the group and class information of said each communication device in the group, the class information specifying whether the communication device is a quality-oriented communication device that prioritizes quality of service over cost or a cost-oriented communication device that prioritizes cost over quality of service; a billing system obtaining unit for obtaining information representing the billing system of said each candidate operator; a quality information obtaining unit that obtains quality information that specifies quality of service provided to said each communication device by said each candidate operator; a first selecting unit for selecting, for each quality-oriented communication device in the group, a candidate operator out of the plurality of the candidate operators that is determined based on the quality information to provide the best quality of service to the communication device; and a second selecting unit for selecting, for each cost-oriented communication device in the group, based on the billing system and a number of quality-oriented communication devices assigned to said each candidate operator as a result of the selection by the first selecting unit, a candidate operator out of the plurality of the candidate operators such that a total cost for all the communication devices in the group becomes lowest. a receiving unit (201 for receiving group information that defines the group and class information of said each communication device in the group, the class information specifying whether the communication device is a quality-oriented communication device that prioritizes quality of service over cost or a cost-oriented communication device that prioritizes cost over quality of service; a billing system obtaining unit for obtaining information representing the billing system of said each candidate operator; a quality information obtaining unit that obtains quality information that specifies quality of service provided to said each communication device by said each candidate operator; a first selecting unit for selecting, for each quality-oriented communication device in the group, a candidate operator out of the plurality of the candidate operators that is determined based on the quality information to provide the best quality of service to the communication device; and a second selecting unit for selecting, for each cost-oriented communication device in the group, based on the billing system and a number of quality-oriented communication devices assigned to said each candidate operator as a result of the selection by the first selecting unit, a candidate operator out of the plurality of the candidate operators such that a total cost for all the communication devices in the group becomes lowest.