After the user purchased an information apparatus, even when he turns on a power source without setting a line and automatic line identification fails, a demonstration mode is not started, and when the information apparatus exists in a shop, the demonstration mode can be certainly started by the minimum number of steps. The information apparatus has: a communicating situation identifying unit for identifying a communicating situation of the information apparatus; a display unit for displaying the demonstration mode and an electronic key for promoting sales of the information apparatus; an operation unit for selecting the electronic key; and a control unit for identifying the communicating situation when the power source is turned on, starting a regular mode in which the information apparatus is normally used when the identification of the communicating situation succeeds, and displaying a demonstration mode selection display screen to select start-up of the demonstration mode when the identification of the communicating situation fails.