Text character input device and display change method

An objective of the present invention is to allow easily changing either sizes or number of input areas in which a text character is inputted in a prescribed text character input area. A text character input device comprises: a display unit which displays a text character input area of a prescribed size having one or more input areas wherein text characters are inputted; a detection unit which detects a specified operation which changes either the sizes or the number of the one or more input areas; a change unit which changes either the sizes or the number of the one or more input areas when the specified operation is detected by the detection unit; and a control unit which displays the one or more post-change input areas on the display unit.