The purpose of this study is to examine the effects of "grasping-form" of non-annular test figure (TF) on simultaneous brightness contrast in Koflka-ring type patterns. To systematically manipulate the figural unity under brightness contrast, we used a color-graphic system to investigate the stimulus conditions (five degrees of separation) of the TF. Utilizing the two attitudes for grasping the TF (i.e., as a unified whole or two segmented parts), seven subjects were instructed to adjust the comparison figure to match the apparent brightness of two TF sections overlapping on a black-white inducing figure with gray background. The results revealed that the magnitudes of brightness contrast (MBCs) in the TF decreased as the degree of separation decreased for both grasping attitudes. The average MBCs were significantly larger in the segment-grasping than in the unity-grasping, although the decrease-trait of the MBCs generally corresponded to each other in either type of grasping-form. As a consequence, the grasping-form attitudes seem to represent a kind of "image-manipulation" by the observers, who may perceive the configuration of the TF at various information-processing stages without being directly influenced by the TF appearance.