Transmission mechanism of spinning fishing reel

A transmission mechanism of a spinning fishing reel, comprising:

• a transmission shaft rotatable about an axis and provided with a shaft body having a non-circular outer periphery, a first end, and a second send opposite to the first end, an axial hole recessed from the first end of the shaft body along the axis, an internal thread section on a wall of the axial hole, and at least one cut slit extending from the first end of the shaft body toward the second end of the shaft body and being in communication with the axial hole;
• a gear disc including a tube portion with a non-circular inner periphery, through which the shaft body of the transmission shaft is inserted such that the gear disc is drivenable by the transmission shaft to rotate;
• and
• a bolt including a head, a shank extending from the head, and an external thread section on the shank;
• wherein the shank of the bolt is inserted into the axial hole of the transmission shaft in a way that the external thread section is screwingly engaged with the internal thread section, and the head of the blot is abutted against an end of the tube portion of the gear disc, such that a part of the outer periphery of the shaft body, which is adjacent to the first end of the shaft body, is firmly abutted against the inner periphery of the tube portion of the gear disc.