  We examine a superpotential for an SO(10) GUT and show that if the parameters
of the superpotential are in a certain region, the SO(10) GUT has an
intermediate symmetry ${\rm SU(2)}_L \otimes {\rm SU(2)}_R \otimes {\rm
SU(3)}_C \otimes {\rm U(1)}_{B-L}$ which breaks down to the group of the
Standard Model at an intermediate scale $10^{10-12}$ GeV. In the model by the
breakdown of the symmetry right-handed neutrinos acquire mass of the
intermediate scale through a renormalizable Yukawa coupling.
