The mode of color appearance is determined not solely by physical properties of the stimulus but also by the conditions of surrounding stimuli. Coplanar ratio hypothesis suggests that the information provided in the same plane plays an important role in the judgment of lightness. We measured the upper-limit luminances of the test stimulus for the surface-color mode in a three-dimensionally represented environment to study the effects of depth and luminance conditions on the mode perception. The test stimulus and two array-type surrounding stimuli composed of 10 different colors were presented at different depths. The test stimulus was presented at three different depths. Subjects set the luminance of the test color to the point where it just ceased to appear in the complete surface-color mode. The upper-limit luminances of the test colors varied as the luminances of the surrounding stimulus displayed in the same depth changed. Our results indicate that the perception of the surface-color mode is mainly determined by the stimulus displayed in the same depth. These results support that belongingness – to which group in the environment the stimulus belongs – is important, and that the mode of color appearance is determined coplanar in a three-dimensional environment.