Experimental data obtained by the magnetometers on Mars 3 (1972) at heights of 1000 km on the day side and Mars 5 (1974) at heights up to 9000 km on the dusk and night sides during opposite polarities of the interplanetary magnetic field show that Mars has an intrinsic magnetic field. The magnetic moment of the Martian dipole is M?64Rm3=2.5⋅1022 G cm3, and the equatorial dipole field at the surface of the planet is 64 &ggr;. The topology of lines of force on the day and night sides can be explained best if we assume that the magnetic dipole axis of Mars is tilted less than 15¿--20¿ from the rotation axis. The bow shock position observed on the day side in agreement with the hypothesis of an intrinsic Martian magnetic field.