PROBLEM TO BE SOLVED: To provide a fishing spinning reel having an excellent weight balance that sufficiently reinforces arm portions by a reinforcing member without disturbing a fishing line operation and efficiently reduces the weight of the reinforcing member to reduce the weight of a rotor as much as possible.SOLUTION: The fishing spinning reel includes the reinforcing member 10 for connecting the side part of one arm portion 3b to the side part of the other arm portion 3b. When the smallest sectional area among cross-sections formed by cutting the reinforcing member 10 at any angle at the part of the reinforcing member 10 most remote along the axial direction of the rotor 3 from a fishing line guide portion 3d is A, the center of the cross-section A is G, a plane including the cross-section A is P and the root of a vertical line dropped from the central point of the fishing line guide portion to a plane P is K, a relation: I(m)
