Application of color coding to a jack board-type display has not yet been tried. The purpose of this paper is to study the effects of color coding on a jack board-type display. Ten subjects searched 10*20 arrays of numbers for the presence or absence of a color coding. Five colors were used for the coding. Three subjects were selected among 10 subjects to repeat 11 times the above experiments. Detection time was reduced by 6.6% for the color coding condition. Three subjects did not show any results different from those in their inexperienced state, except the learning effect during repetition of the experiments. The results imply that the color coded jack board-type display may be efficient either to inexperienced subjects or to experienced subjects.