PROBLEM TO BE SOLVED: To provide a fish detection system which easily and inexpensively acquires information on a school of fish, water temperature and the like at a distant place suitable for casting with a device fixed to a rod.SOLUTION: A fish detection system is constituted by having a weight with a detection function including in a trunk: first ultrasonic wave transmission/reception means for performing fish detection； temperature detection means for performing water temperature detection； second ultrasonic wave transmission/reception means for performing information communication using a line as a transmission path； control means for performing control of each means； and power source supplying means for driving each means, fixing an information display device including: ultrasonic wave transmission/reception means for performing information communication using a line connected to the weight as a transmission path； control means for performing control such as analysis of information acquired by the ultrasonic wave transmission/reception means and monitor display of the result； power source supplying means for driving each means to the handle of a rod, and fixing a line holder for performing ultrasonic transmission with the ultrasonic wave transmission/reception means in the information display device by holding the line to the vicinity of the information display device.SELECTED DRAWING: Figure 1【課題】投げ釣りに好適な遠方の魚群や水温などの情報をロッドに固定した装置にて簡単且つ安価に取得する、魚群探知システムを得る。【解決手段】魚群探知を行う第一の超音波送受波手段と、水温検出を行う温度検出手段と、ラインを伝送路として情報通信を行う第二の超音波送受波手段と、前記各手段の制御を行う制御手段と、前記各手段を駆動する電源供給手段とをおもりの胴部に内蔵して構成した探知機能付おもりと、これに結ばれたラインを伝送路として情報通信を行う超音波送受波手段と、該超音波送受波手段より取得した情報の解析と結果のモニタ表示などの制御を行う制御手段と、前記各手段を駆動する電源供給手段とを内蔵して構成した情報表示装置をロッドの手元に固定し、前記ラインを挟持して情報表示装置内の超音波送受波手段と超音波伝送を行わせるラインホルダを当該情報表示装置の近傍に固定して構成したシステムとする。【選択図】図１
