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An active compensation method is presented as the method of improvement of measuring conditions in an unshielded laboratory room. The disturbing magnetic field is picked up by a SQUID magnetometer. The output signal controlled by electronics feeds the compensation coil set, which generates a magnetic field opposite to the disturbing magnetic field and magnetic ambient noise is reduced. The combination of the active compensation technique and a gradiometer is used to eliminate low-frequency magnetic disturbances. An attenuation of more than 40 dB at low frequencies was obtained. The comparison with other compensation techniques is discussed, as is the problem of whether active compensation reduces magnetic disturbances when changing the measuring position. The active compensation technique is performed in all directions of an orthogonal system.