A laminated core formed in a ring shape by bending bendable connecting portions of a laminated connected core segment, the laminated connected core segment being formed by laminating a predetermined number of straight connected core segments, each of the straight connected core segments having segment yokes connected together by the bendable connecting portions and having a V-shaped cutout formed in a radially inward section of the connecting portion, the V-shaped cutout opening in a radially inward direction, each of the segment yokes having a magnetic pole piece, the straight connected core segments being laminated and bent at the connecting portions in a ring shape, the straight connected core segment is characterized by: the V-shaped cutout opening with an opening angle of 360°/n wherein n is a number of magnetic poles in the laminated core, a slit formed in the yoke located radially outward from the connecting portion, the slit dividing the adjacent segment yokes located radially outward from the connecting portion and being radially aligned with the V-shaped cutout; a first through-hole having a circular arc formed in a radially outward end of the V-shaped cutout in contact with the connecting portion; and a second through-hole having a circular arc formed in a radially inward end of the slit in contact with the connecting portion, the second through-hole having a curvature radius larger than that of the first through-hole; the curvature radius of the second through-hole is 2 to 15 times a thickness of the connected core segment; and the width (w) of the connecting portion is within 1 to 5 times the thickness of the connected core segment. each of the straight connected core segments having segment yokes connected together by the bendable connecting portions and having a V-shaped cutout formed in a radially inward section of the connecting portion, the V-shaped cutout opening in a radially inward direction, each of the segment yokes having a magnetic pole piece, the straight connected core segments being laminated and bent at the connecting portions in a ring shape, the straight connected core segment is characterized by: the V-shaped cutout opening with an opening angle of 360°/n wherein n is a number of magnetic poles in the laminated core, a slit formed in the yoke located radially outward from the connecting portion, the slit dividing the adjacent segment yokes located radially outward from the connecting portion and being radially aligned with the V-shaped cutout; a first through-hole having a circular arc formed in a radially outward end of the V-shaped cutout in contact with the connecting portion; and a second through-hole having a circular arc formed in a radially inward end of the slit in contact with the connecting portion, the second through-hole having a curvature radius larger than that of the first through-hole; the curvature radius of the second through-hole is 2 to 15 times a thickness of the connected core segment; and the width (w) of the connecting portion is within 1 to 5 times the thickness of the connected core segment. the V-shaped cutout opening with an opening angle of 360°/n wherein n is a number of magnetic poles in the laminated core, a slit formed in the yoke located radially outward from the connecting portion, the slit dividing the adjacent segment yokes located radially outward from the connecting portion and being radially aligned with the V-shaped cutout; a first through-hole having a circular arc formed in a radially outward end of the V-shaped cutout in contact with the connecting portion; and a second through-hole having a circular arc formed in a radially inward end of the slit in contact with the connecting portion, the second through-hole having a curvature radius larger than that of the first through-hole; the curvature radius of the second through-hole is 2 to 15 times a thickness of the connected core segment; and the width (w) of the connecting portion is within 1 to 5 times the thickness of the connected core segment.