The present invention relates to a fishing bobber that is used when freshwater fishing, one of the existing fishing crucian fishing, if the crucian eats a prey attached to the fishing hook, the fishing bobber floats on the surface for fishing and fishing The bobs are divided into middle-class fishing that goes below the surface of the water.The present invention is a structure that can test the performance and characteristics of the fishing bobber used in the middle-layer fishing, its configuration is sewn on the rod pin attached to the solenoid and sensor added to the coil wound around the bobbin penetrated to generate a magnetic field It is divided into a flow display part equipped with holder and steam rubber and a power case which mounts a steam case on the upper part of the casing and supplies a constant electric signal to the solenoid to generate a magnetic field.In general, when fishing, crucian carp eats bait, and inhales and spits out instantaneously. This behavior is expressed differently depending on the temperature of the water temperature and caution, which is transmitted to the bobber and expressed externally. To see this is to catch crucian carp. When a phenomenon occurs when the crucian carp is formed, an electrical signal is generated at the power supply unit, and a magnetic field is generated in the solenoid, and the sensor added to the leg of the bobber to be tested is pulled down. If you install multiple steaming cases containing water and generate electrical signals of the same current at the same time, each of the steaming cases inside the steaming case generates magnetic fields and pulls them down. This large and dull steaming will be small in motion.The characteristics and performance of the bobber to be tested by the above method can be tested by the magnetic field of the solenoid and the sensor weight.Crucian fishing, middle fishing, bobber, bottom fishing,본 발명은 민물낚시를 할때 사용되는 낚시용 찌에 관한 사항으로, 기존 낚시중의 하나인 붕어낚시는 붕어가 낚시바늘에 달린 먹이를 먹게되면 낚시용 찌가 수면