Proposes a magnetic measurement principle to develop a balance sensor. Basically, the sensor is composed of a spherical vessel sealing a certain amount of liquid, a mushroom-shaped float and a permanent magnet. The circular plated magnet is fixed on the root of the float stem. As the liquid moves in the vessel, the float changes the position of the magnet. And the Hall effect devices located around the vessel sense the change of balance with the aid of a signal processor. The density of the Hall effect devices and the algorithm for determining the direction of the resultant acceleration are considered. Also, the results of experiments for magnet's position and the angle of balance are shown. The proposed method is effective in detecting all directions of the resultant acceleration of motion and gravity with uniform resolution, since the sensor has no rotation axes.