For the liquid crystalline(LC) solution of Poly( gamma -benzyl L-glutamate),(PBLG), / 1,1,2-trichloroethane, which gives a nematic texture aligned homeotropically at a glass surface, the effect of DC field applied perpendicularly to the director in a homeotropic texture was investigated by microscopic optical measurements. An increase of the DC field above a threshold generates some planar texture at the negative electrode and the texture develops with a distinct boundary between the homeotropic and the planar ones. After the field direction was inverted, the boundary begins to move backward into the electrode, and at the same time, the planar texture to develop slowly from the another electrode. Under a fixed strength of the field, the ratio of the homeotropic and the planar areas is kept constant during transforming process after an inversion and the value depends on the field strength. The phenomenon may be qualitatively associated with the balance between some electrostatic interaction of the polar terminal groups of polymer with the ionic charges on the glass surface and the dielectric instabilities due to the large dipole along the molecular axis.