A mobile terminal apparatus 1 uses an acceleration sensor as a tilt angle sensor 24, and realizes various applications based on this detection result. A processing unit 10 counts the number of steps of a human based on acceleration components of low frequency detected by the tilt angle sensor that detects the acceleration components. At that time, the acceleration component of an axis among three axes which most approximates a gravity axis is mainly used. A viewpoint relative to a three-dimensional object or a three-dimensional space displayed on a display unit 36 is moved. By effectively utilizing the detection result of the tilt angle sensor, it is possible to realize a mobile terminal apparatus 1 featuring greater usefulness.