PURPOSE: To prevent discoloring at overlapped parts of patterns by providing a display section with a plurality of memory means with the color attributes and mutual preference of pattern data set to generate a display signal based on the color attributes and the preference.

CONSTITUTION: Pattern data sent from a measuring section through a system bus 20 are written into memory areas R, G, B, EX1 and EX2 separately according to the respective attributes thereof. The data in the areas R, G, B, EX1 and EX2 are read out sequentially and inputted into a preference circuit 2. The area EX1 stores the pattern data for rules, the area EX2 the pattern data for a marker cursor and the areas R, G and B the pattern data of measurement results to be displayed. With a parallel reading of the areas EX1, EX2, B, G and R, read signals ex1, ex2, (b), (g) and (r) are inputted into a circuit 22. Thus, the display 30 performs an indication in the color attributes and preference set to prevent discoloring at overlapped parts of patterns.