A telephone book data processor includes: a connection element for connecting to an external device via a short range communication manner to transfer a telephone book data; a telephone book data obtaining element for obtaining the telephone book data; a memory having multiple memory regions for storing the telephone book data; and a controller for executing a telephone book data transfer process and a telephone book data utilizing process. The controller defines one memory region as an object of the telephone book data transfer process and another memory region as an object of the telephone book data utilizing process. The controller executes the telephone book data utilizing process with using the telephone book data in the another memory region while the controller executes the telephone book data transfer process for storing a new telephone book data in the one memory region.