Provided are an information inputting device and an information inputting method capable of inputting information to a portable electronic apparatus by using a touch panel and an electronic pen. In the information inputting device and the information inputting method, the portable electronic apparatus including a touch panel is combined with a receiver which receives an ultrasonic wave signal and a reference signal, so that it is possible to input information by using the touch panel and to accurately input information by using the electronic pen which emits the ultrasonic wave signal.