Using a two-rotation-axis goniometer inserted into electron spin resonance equipment, for the first time, we successfully observed the three-dimensional distribution of the g-values of the composite Haldane spin chains in IPA-CuCl3. The result indicated that the Cu 3d hole orbital pattern spreads along a ladder-spin network plane. Furthermore, the superexchange interaction between the planes was not expected to be large as compared with that within the plane, irrespective of the Cu-Cu distance and the formation of superexchange paths.