A rotor of a spinning reel is provided to prevent the deformation or damage of a cover member by using a back cover member and an outer cover member. A rotor of a spinning reel comprises a rotor main body(33) which comprises a common connection part capable of being pivotally connected to a pinion gear, a first rotor arm(31) extended from the first part of the back part of the connection part to the front part with the interval with the connection part, and a second rotor arm(32) extended from the second part of the back part of the connection part to the front part with the interval with the connection part; an outer cover member(36a,36b) which covers the outer part of at least one of the first and second rotor arms; a back cover member(37) which covers the back part of the connection part; and an adhesion projection(38a,38b) which is installed at the rotor main body between the rotor arm where the outer cover member is installed and the connection part, is projected toward the adhesion part of the outer covert member and the back cover member, and has a first adhesion surface comprising the plane adhered to the outer cover member and a second adhesion surface comprising the plane adhered to the back cover member. The cross section between the first and second adhesion surfaces are exposed.