  In the BRST-BFV scheme for noncommutative D-branes with constant NS
$B$-field, introducing ghost degrees of freedom we construct the gauge fixed
Hamiltonian and corresponding effective Lagrangian invariant under nilpotent
BRST charge. It is also shown that the presence of auxiliary variables
introduced via the improved Dirac formalism plays a crucial role in the
construction of the BRST invariant Lagrangian.
