A SPINNING REEL SPOOL COUPLING STRUCTURE HAS A PIN INSERTION PORTION (8D), AN ANTI-ROTATION PIN (50), A RETAINER (51), AND AN ANTI-ROTATION GROOVE (24C). THE PIN INSERTION PORTION (8D) HAS A THROUGH HOLE PASSING THROUGH THE SPOOL SHAFT (8). THE ANTI-ROTATION PIN (50) INCLUDES A FIRST ANTI-ROTATION PORTION (50A), A FITTING PORTION (50B), AND A SECOND ANTI-ROTATION PORTION (50A). THE FITTING PORTION (50B) ADJOINS THE FIRST ANTI-ROTATION PORTION (50A), AND FITS INTO THE PIN INSERTION PORTION (8D). THE SECOND ANTI-ROTATION PORTION (50C) EXTENDS FROM THE FITTING PORTION (50B) AND HAS A DIAMETER GREATER THAN THAT OF THE PIN INSERTION PORTION (8D). THE RETAINER MEMBER (51) PREVENTS THE ANTI-ROTATION PIN (50) FROM BEING DETACHED FROM THE SPOOL SHAFT (8), IS DISPOSED ON AN OUTER PERIPHERAL SIDE OF THE FIRST ANTI-ROTATION PORTION (50A), AND HAS AN AXIAL LENGTH SUCH THAT THE RETAINER MEMBER (51) CONTACTS THE SPOOL SHAFT (8). THE ANTI-ROTATION GROOVE (24C) IS FORMED TO EXTEND IN A DIRECTION SUBSTANTIALLY PERPENDICULAR TO A LENGTH OF THE SPOOL SHAFT (8), AND ENGAGES THE SECOND ANTI-ROTATION PORTION (50C). (FIG. 3)
