The present invention relates to a spool 4 for a spinning reel being mountable on a spool shaft 15. The spool 4 includes a spool body 42 that rotates with respect to the spool shaft 15. The spool 4 also includes a drag mechanism 43 between the spool body 42 and the spool shaft 15 to apply a braking force against a rotation of the spool body 42. The spool 4 further includes a radiator 44 in the spool body 42 and in contact with the drag mechanism 43. The radiator 44 rotates with respect to one of the spool body 42 or the spool shaft 15. The radiator 44 does not rotate with respect to the other one of the spool body 42 or the spool shaft 15. The invention further relates to a spinning reel comprising such a spool 4.本發明提供一種能夠有效地降低引曳機構之溫度上升之捲線器之捲軸。 本發明之捲線器1之捲軸4安裝於捲軸之軸15。本捲軸4具備捲軸本體42、引曳機構43、及散熱片44。捲軸本體42構成為能夠相對於捲軸之軸15旋轉。引曳機構43配置於捲軸本體42及捲軸之軸15之間。引曳機構43對捲軸本體42之旋轉進行制動。散熱片44於捲軸本體42之內部與引曳機構43接觸。散熱片44構成為能夠相對於捲軸本體42旋轉。散熱片44構成為相對於捲軸之軸15不能旋轉。
