PURPOSE: To scroll character strings without any break by scrolling a screen in block units having specific meaning among plural character strings.

CONSTITUTION: An original sentence is inputted from a key input part 2 and equivalents to the original sentence are retrieved in a dictionary memory 3; when data of original sentence lines and equivalent lines are written in a document memory 7 alternately, line by line, a master association flag '0' is added to the line head data part of the original sentence line and a slave association flag '1' is added to the line head data part of the equivalent line. For a scrolling process, character string data having the slave association flag following the main association flag are regarded as one block over a look at the association flags on the uppermost and lowermost lines on the screen, and the data are scrolled so that they are displayed on the screen in block units.