To suppress rise in a manufacturing cost while maintaining the precision of a rotor body of a spinning reel and to lighten the rotor body while maintaining the strength.

This rotor 3 of a spinning reel is installed rotatably in a reel body 2, guides a fishing line to a spool 4, and has a rotor body 16, a bail arm 17, a bail reversing mechanism 19 and a case member 18. The rotor body 16 has a cylindrical part 30 fitted rotatably in the reel body 2, and a first rotor arm 31 and a second rotor arm 32 placed in such a way as to face each other and to have housing spaces in their insides. The cylindrical part 30 and the rotor arms 31, 32 are integratedly molded. The bail arm 17 is installed in a rockable state on the tips of both rotor arms. The bail reversing mechanism 19 is housed in the housing space in order to be returned to a fishing line- winding attitude. The case member 18 covers the housing space within the first rotor arm 31 from the side of the cylindrical part 30 and can be equipped with the bail reversing mechanism 19.