It is shown that CaCu3Ti4O12 grains in a polycrystalline specimen have domains and comparatively
thick domain walls. The orientations of the domains within a grain were observed to be slightly
tilted toward each other, suggesting the presence of lattice distortions. Multiple reflection spots in
the electron diffraction pattern and misfit dislocations were also found in the domain walls. Kelvin
probe force microscopy showed the variation in the surface potential of a grain by external electric
fields, demonstrating the polarization of dipole moments. The influence of the local distortions on
the formation of dipole moments is discussed in terms of the deviation from the cubic symmetry due
to the small misfit between domains in a single grain of CaCu3Ti4O12 polycrystals.