As the structure for performing the alignment in the axes between the rotor 3 and the stator 1 a, in the electric rotating machine having the inner rotor structure as shown in the FIG. 1, there is taken a method, in which the assembling is performed, by making the outer periphery of the fitting portions 35 a and 35 b of the bearing holder portions 6 a and 6 b formed from material, such as aluminum