A data converting system converts CRT display data into display data for another display unit such as a liquid crystal display unit by use of a memory. The system includes a data load controller which selects one segment of data out of two segments of data in the CRT display data successively while changing the segment position to be selected alternately in every two frame scanning periods so that the CRT display data for one complete picture is written into the memory in two frame scanning periods, i.e., a segment is written into the memory once for every two adjacent segments. Display data is read out of the memory in the data form conformable to the other display unit.