Using the direct Liapunov method, the almost certain asimptotic instability of the Tymoshenko beam is investigated in the work. The beam is compressed by a time-varying stochastic axial force. As a difference from the classical theory, the influence of the torsional inertia of the cross-section and shear deformation were taken into account. Functional von Liapunov was constructed here according to the Parks - Pritchard method and the obtained results represent a generalization in relation to the results obtained according to the classical beam theory.