A handle arm mounting structure for a fishing reel includes a fastening section and a washer member. The fastening section has a first non-circular hole configured to engage non-rotatably with a non-circular section of a handle shaft. The washer member has a circular disk-like section and an engaging protrusion and is configured to be mounted in an axial direction on the handle shaft. The circular disk-like section has a second non-circular hole that engages with the non-circular section. The engaging protrusion protrudes toward the first non-circular hole from a periphery of the second non-circular hole. The engaging protrusion has an inside surface configured to engage with the non-circular section and an outside surface having a first tapered surface that tapers toward a tip end and engages with the first non-circular hole.
