PURPOSE: To make possible the input of the new data in the same manner as the normal input field without erasing during the image surface erasing by providing a memory portion memorizing a duplicate field region at CRT terminal.

CONSTITUTION: The data inputted from the key input portion is written in the screen data memory SDM in the screen memory 4. In this instance, in the screen control memory SCM, the protect region p and a duplcate region d are disposed correspondingly to the memory data of the memory SDM to constitute the format. Thus, after carrying out the input processing for the first note and in the case of inputting the next note, the regions p and d are left as they are and other entry field is erased. Then, the data is inputted to the respective entry fields including the region d, and after finishing this, FE key is operated.