To clarify the characteristics of visual search that are controlled by spatial frequency, we measured the scan path during eye movement in response to visual stimuli. A target stimulus with the spatial frequency of 1/f (where β is the slope of power spectral density of luminance in an image) was embedded in a background stimulus with white (1/f ) characteristics. An instruction-based task was employed in this study, wherein a subject searches for the target as rapidly as possible and fixates on it. Participants were six healthy males aged 21-22 years. In the task, a threshold for spatial frequency that was the minimum value required by the subjects for the search corresponded to β =∼ 0.2 - 0.3. This finding has potential application in the design of visual presentation media, such as signs and tablets, by providing ease of viewing to the user. β 0