A communication terminal capable of obtaining assist data without making a configuration of an information providing device for transmitting the assist data complicated is provided. Processing performed by a communication terminal includes the steps of: storing an obtained identifier in a buffer area for a base station for which assist data should be obtained and a buffer area for a standby base station; obtaining an identifier of a wireless base station from a received signal and storing the identifier in a RAM; storing an identifier of a wireless base station after change in the buffer area for a standby base station; and storing the identifier stored in the buffer area for a standby base station in the buffer area for a base station for which assist data should be obtained when the identifier stored in the buffer area for a standby base station is not stored in the buffer area for a base station for which assist data should be obtained.