A commodity sales data processing apparatus including a display unit configured to display various kinds of information includes an angle-of-field setting unit configured to set an angle of field of a display screen of the display unit to a first angle of field or a second angle of field narrower than the first angle of field. When checkout processing is started, an angle-of-field control section of the commodity sales data processing apparatus causes the angle-of-field setting unit to operate and set the angle of field of the display screen of the display unit to the second angle of field.