Measurements of ion fluxes in close vicinity to Mars have been made by the space probes Mars 2 and Mars 3 during 1971--1972. Analysis of measurements confirms the earlier preliminary conclusion by these authors about the existence of bow shock wave near Mars. Seventeen crossings of the bow shock are used to obtain the mean location of the bow shock and to estimate the dimension of the obstacle. The mean distance to the bow shock subsolar point is estimated as ~1200 km, and the corresponding height of the stagnation point, as ~400 km. Anomalously far positions of bow shock, ~2800 km, have been observed by the two satellites. New features of the interaction region have been observed. This region is characterized by high-intensity fluxes of ions with temperatures of some tens of electron volts and convective velocities well below the convective velocity in the magnetosheath. This 'cushion' of hot ions is situated inside the magnetosheath but above the Martian ionosphere. Intercomparison of these measurements with magnetic field data shows that observations of decelerated hot ions usually coincide with an increase of the magnetic field up to 15--30 &ggr;. A gradual change of the ion transport velocity at the transition from the magnetosheath to the cushion of hot ions favors the piling up model of magnetic field rather than the model of the internal dipole field of Mars.