Control data indicating the vertical start positions of display characters is written into the locations of a video RAM determined by a common column address and a plurality of column addresses. In each horizontal synchronizing period, all control data is read in sequence from the video RAM and set in sequence in a vertical start position register. A match is found between the contents of the vertical position counter indicating the current vertical position and the contents of the vertical start position register. When they match, after the horizontal synchronizing period, the video RAM is accessed with the control data as the vertical position start address.