A line guide mechanism for a spinning reel includes a bail support member movably connected to one of the pair of rotor arms, a fixed shaft fixed to the bail support member, a line roller rotatably supported by the fixed shaft to guide the fishing line to the spool, a bail having an end supported by the bail support member via the fixed shaft to guide the fishing line to the line roller, a cover member on the end of the bail to cover a part of the line roller, and a projection member on the bail support member and having a line slack prevention portion including a first part extending in an axial direction of the fixed shaft and facing the line roller in a radial direction of the fixed shaft closer to an axis of the fixed shaft than an outer peripheral surface of the cover member.