In a portable telephone, a sensor constructed of, for example, a 3-axial acceleration sensor is built in the vicinity of a display unit which is provided on a main body of the portable telephone. When a user moves the display unit along a vertical direction (Z-axis direction) with respect to a display screen thereof while the user holds the appliance main body, the sensor senses both a move direction and a move amount of the display unit, and thus, information displayed on the display screen of the display unit is enlarged, or compressed in display magnification defined in response to the sensed move amount. As a result, a display size of the information displayed on the display screen can be changed in such a manner that the user may have such a natural feeling achieved by moving a magnifying glass.