The present invention relates to a fishing reel equipped with a loose-proof reinforcing handle. In the case of existing handle shafts in which an end portion has an idle rotation prevention flat portion in which a handle arm idle rotation prevention coupling is formed by side cut such as U cut, handle nut fastening and fixing results in handle nut loosening or handle shaft damage in a case where a load is applied to the handle arm in a fishing line winding situation or the like due to a gap between the flat portion of the handle shaft and the handle nut. In order to tackle this problem, the present invention adopts a loose-proof plug placed in a first flat portion of a handle shaft and having an auxiliary male screw portion corresponding to an end portion first male screw portion. The fishing reel equipped with the loose-proof reinforcing handle according to the present invention is configured to constitute the loose-proof reinforcing handle by an ordinary fishing reel including the handle shaft having a first male screw portion in an end portion with the handle linked to a spool, an idle rotation prevention first flat portion superposed on the first male screw portion, and a stopper in a lower end portion of the first flat portion, the handle arm equipped with a coupling hole that is inserted into the first male screw portion having a non-circular structure for idle rotation prevention by the first flat portion and placed in the stopper, a handle knob provided in an end portion of the handle arm, the loose-proof plug placed in the first flat portion of the handle shaft and having the auxiliary male screw portion corresponding to the first male screw portion, and the handle nut coupled with an assembly male screw portion formed by the first male screw portion and the auxiliary male screw portion and fixing the handle arm locked into the stopper.본 발명은 핸들암의 공회전 방지 결합을 U컷과 같은 사이드컷 등의 방식으로 형성된 공회전 방지 플랫부를 단부에 갖는 기존 핸들샤프트의 경우 핸들너트를 체결하여 고정하여도 핸들샤프트의 플랫부와 핸들너트 사이에 유격으로 인하
