Dependence of the electron multiplication factor on the bias voltage was considered for the blocked impurity band (BIB) detector. It was found that in high gain BIB detectors multiplication factor self-stabilization can be achieved. When bias voltage V(B) increases, the multiplication factor curve flattens, starting at a certain value V(B). This can be explained by the presence of an electric field and electron current in the neutral region of the BIB detector IR-active layer.