Problems exist in areas such as image visibility, endurance of the device, precision, miniaturization, and electric power consumption in an information device having a conventional resistive film method or optical method pen input function. Both EL elements and photoelectric conversion elements are arranged in each pixel of a display device in an information device of the present invention having a pen input function. Information input is performed by the input of light to the photoelectric conversion elements in accordance with a pen that reflects light by a pen tip. An information device with a pen input function, capable of displaying a clear image without loss of brightness in the displayed image, having superior endurance, capable of being miniaturized, and having good precision can thus be obtained.