  We discuss an extension of the Resta's electronic polarization to
non-Hermitian systems with periodic boundary conditions. We introduce the
``electronic polarization'' as an expectation value of the exponential of the
position operator in terms of the biorthogonal basis. We found that there
appears a finite region where the polarization is zero between two
topologically distinguished regions, and there is one-to-one correspondence
between the polarization and the winding number which takes half-odd integers
as well as integers. We demonstrate this argument in the non-Hermitian
Su-Schrieffer-Heeger model.
