An electronic paper is mounted on a paper mounting unit on which the electronic paper is mounted detachably. When a user operation is performed on the display screen of the electronic paper, the user operation position with respect to the display screen of the electronic paper is detected by the operation position detecting unit of the paper mounting unit. The data corresponding to the detected user operation position with respect to the display screen of the electronic paper is transmitted to the electronic paper via mutual communication units. The nonvolatile display unit of the electronic paper displays the data. This enables the data corresponding to the user operation on the electronic paper to be displayed on the nonvolatile display unit.