Elliptic flow at ultrarelativistic energies is interpreted as an effect of pressure in the interaction region. It is thus sensitive both to the eqaution of state of nuclear matter and to the degree of thermalization reached in the system. The flow of heavier particles is particularly interesting as it is less sensitive to the freeze-out temperature and thus more directly reflects conditions at the early stage of the collision than the flow of light particles. The elliptic flow for Lambda hyperons has been measured by NA49 experiment in semicentral Pb+Pb collisions at 158 A GeV. The standard method of correlating particles with an event plane has been used. Measurements of v2 near mid-rapidity are reported as a function of centrality and transverse momentum. Elliptic flow of Lambda particles increases both with the impact parameter and with the transverse momentum. It is compared with v2 for pions and protons as well as with hydrodynamical model predictions.