A one-region parabolic plane moving boundary problem in vacuum freeze drying with heat generation and unknown a priori sublimation temperature T-S(t) at moving interface of ice sublimation, was formulated. It is adequate for vacuum freeze drying of biomaterials at combined radiative-microwave heating. This model takes into account steady capacity of internal heat generation caused by microwave heating. Numerical model equations were solved by the explicit method of finite differences. Results of computations enable estimation of the mu (II) parameter influence on freeze drying curve.