  The paper is devoted to the calculation of the two-loop O(alpha_s y^2) and
O(y^4) MSSM corrections to the relation between the pole mass of the b-quark
and its running mass in DR scheme. To evaluate the needed diagrams the large
mass expansion procedure is used. The obtained contributions are negative in
most of the regions of the parameter space and partly compensate the positive
O(alpha_s^2) contribution calculated earlier.
