A voice discriminating tag for making a reception voice and a transmission voice distinguishable is added to the voice inputted into a cell phone. Further, a volume discriminating tag is added based on a detection result of a volume detector. A CPU converts the voice into character data and image data on the basis of the voice discriminating tag and the volume discriminating tag, referring to various files stored in file devices. The converted data is outputted to a display panel on which the character data corresponding to the transmission voice and the character data corresponding to the reception voice are shown in time series so as to have different colors. The character data is shown in a literal type corresponding to a volume level.