A method for automatically changing a service area of a wide area pager integrated with a Second Generation Digital Cordless Telephone (CT-2) is provided. The method includes the step of receiving service area information by the CT-2 and transmitting the service area information to the wide area pager, when a radio paging mode is performed. The service area information transmitted to the wide area pager from the CT-2 is compared with preset service area information in the wide area pager. The preset service area information in the wide area pager is then changed to the service area information transmitted to the wide area pager, when the preset service area information is not identical to the transmitted service area information.