A reel unit for a spinning reel includes a reel body, a rod attachment leg that is formed integrally with the reel body, and a reinforcing member that is coupled to the reel body by being mounted opening. The rod attachment leg has an accommodation space that opens longitudinally along the length thereof, and the reinforcing member is mounted in this accommodation space. The reinforcing member is a metal member. A portion of the reinforcing member protrudes from the outer peripheral surfaces of the rod attachment leg. A through hole is formed in the lower portion of the reinforcing member, and a screw is inserted into the through hole to be screwed fast to the reel body. In this manner, the strength of a rod attachment leg on a reel unit of a spinning reel can be increased with an inexpensive structure.