PURPOSE: To improve the operability for data input and edition, by controlling the display of each character in a data buffer by a display device according to the value of attribute bit to each character only when the specific mode is set.

CONSTITUTION: In turning off a mode designation switch, since another input 9 of an OFF circuit is increased to "1" level via a resistor 6, so that when the attribute bit value inputted from a data buffer 1 is either "1" or "0", an output 10 of an OR circuit 5 goes always to "1", and all characters in the buffer 1 are transferred to a display device 2 as they are. On the other hand, when a switch 4 is turned on, one input 9 of the circuit 5 is grounded to be at "0" level, then the level of the output 10 is displayed 2 through an AND circuit 4 only when the value of the attribute bit read out to the input 8 is "1".