A method of assembling a stator core, the stator core having a plurality of segmented cores. Each of the segmented cores has an arcuate yoke portion, a pole portion extending diametrically inwards from the yoke portion, and a tooth portion on a diametrically inner end of the pole portion, the yoke portion having a projection and a groove on circumferential one end and the other end, respectively, thereof. The segmented cores are assembled to form a stator core by circumferentially connecting the segmented cores by fitting a projection in one of adjoining segmented cores into a groove in the other of the adjoining segmented cores, the method including the steps of: arranging the projection circumferentially insertable into the groove, disposing the plurality of segmented cores into an annular shape, and pushing a movable plate downward on a cam which pushes the plurality of segmented cores radially inwards in a manner synchronized with each other such that the projection in each of the segmented cores is fit by press fitting into each of the grooves in the adjoining segmented cores from a circumferential direction.