  We develop the BRST approach to gauge invariant Lagrangian construction for
the massive mixed symmetry integer higher spin fields described by the rank-two
Young tableaux in arbitrary dimensional Minkowski space. The theory is
formulated in terms of auxiliary Fock space. No off-shell constraints on the
fields and the gauge parameters are imposed. The approach under consideration
automatically leads to a gauge invariant Lagrangian for massive theory with all
appropriate Stuckelberg fields. It is shown that all the restrictions defining
an irreducible representation of the Poincare group arise from Lagrangian
formulation as a consequence of the equations of motion and gauge
transformations. As an example of the general procedure, we derive the
gauge-invariant Lagrangian for massive rank-2 antisymmetric tensor field
containing the complete set of auxiliary fields and gauge parameters.
