There is provided a service class control system and the like for facilitating modification of a service class of a terminal device or disabling unauthorized modification of the service class. A service class management server (1) contains service class data for specifying a range of service provided by the user terminals 2-1 to 2-n. When a user terminal 2-k transmits data requiring a start of providing a service, in response to this, service class data indicating the service class of the user terminal 2-k is transmitted to the user terminal 2-k. After receiving the service class data, the user terminal 2-k provides a service of the range specified by the service class data.
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