Mobile telephone capable of retrieving stored data

A user enters a numeric string on a standby screen of a cellular telephone (1), and then presses a predetermined function key, the numeric string being obtained by numerical conversion of a piece of registration information, e.g. a registered destination name of a piece of e-mail, in accordance with an assignment relationship indicated on numerical keys (22) of the cellular telephone. A database (45) in which numeric data obtained by the numerical conversion of a piece of registration information in accordance with the abovementioned assignment relationship and the piece of registration information are associated with each other is previously held in the cellular telephone. In the cellular telephone which recognizes the entry of the numeric string, the database is searched by using the entered numeric string as a search key, so that pieces of registration information associated with numeric data containing the numeric string are extracted. In said database, numeric data including a character delimiter corresponding to a blank character contained in a piece of registration information is registered, and a prefix search also on numeric data subsequent to the character delimiter is performed.