A word processing device with an automatic address-input function comprises a keyboard for inputting a postal code and address; a memory for storing the postal code and address inputted from the keyboard, in correlation with each other; and a processing unit for retrieving a postal code identical with the postal code inputted from the keyboard among postal codes stored in the, memory, for reading an address corresponding to the retrieved postal code from the memory and for making the memory store the address in correlation with a postal code inputted from the keyboard.