The present invention has an object to provide a stator core which assures a favorable workability for coupling core segments and has a favorable magnetic characteristic even when the stator core is composed by coupling core segments which are composed by laminating core division sheets. The manufacturing method of a core for rotary electric machines and a core according to the present invention are configured to form a coupling convexity having an arc-like planar shape and a coupling concavity engageable with the coupling convexity on core segments, compose a serial core segment assembly by engaging the coupling convexity on one of adjacent core segments with the coupling concavity formed on the other core segment so as to be rotatable over 180 degrees, and form a magnetic circuit by bending the serial core segment into an annular form.