To provide a mobile electronic device capable of assisting a user so as to readily designate at least a part of a character string displayed on a screen as a selection range. A display unit displays a screen including a character string. A designated position detection unit detects a position in the screen designated by the user. An inclination detection unit detects an inclination of the mobile electronic device. A selection range setting unit sets at least a part of the character string as a selection range. A start position setting unit sets a start position of the selection range, based on the position designated by the user and detected by the designated position detection unit. An end position moving unit moves an end position of the selection range, based on a result of detection by the inclination detection unit, after the start position of the selection range is set.