<p>The strong magnetic field arrays by using cubic permanent magnets are proposed as a magnetic field source. The magnets are used two types of the magnetized directions: 6 and 18 directions. The array is three-dimensional structure: cube consisting of three, five, seven, and nine cubic magnets on the side. There are two types of the structures: through-hole and dead end in the center. For each cube magnet, the magnetic flux density of the center was calculated by the derived formulae which are solved the area integral by the integral formulae. It is a feature that the calculations are fast. The directions in which the magnetic flux density of the z-axis is maximized were selected, and the sum of their magnetic flux density was obtained. At the same time, each sum of the magnetic flux density of the x-axis and y-axis was selected to be zero. It found that the obtained results are independent of the length of one side. Therefore, the structures can also be combined to cover the structures. Although the operating point of the magnet is not taken into account, it was able to find the arrangements of more than 2 T. It was confirmed that the array of 24 cubes was consistent with the experiment.</p>