Despite the fact that the axial inductor machine is used in various economic sectors, such as aircraft, train – building, etc. there is not a lot of information available about 3D magnetic field calculations of this type of electrical machines, as well as its comparison with 2D calculations. The goal of this paper is to find out if 3D calculation is really necessary for magnetic field investigation in inductor machine. Similar investigations for other types of machines (mostly for asynchronous) are published for example in [1] and [2]. This paper examines a number of magnetic field calculation methods: direct 3D task; 3D task reduced to 2D task; the plane-parallel 2D task; axisymmetric 2D task. Current research is taken from R. Geidarovs’s master thesis [3] whose reviewer was A. Podgornovs. There the magnetic flux density and magnetic flux values were investigated using the finite element method (FEM; see [4] and [5]). Axisymmetric 2D task was found to be unfit for calculations of inductor machines, because in this case the approximations of the magnetic permeability of machines teeth zone must be used. Closest results were obtained between direct 3D and 2D plane-parallel task. In this case, the difference of magnetic flux density (taking into account the scattering) was established less than 2 percent, but for the magnetic flux the difference is about 4 percent.