A usual fishing line take-up reel has a drag mechanism for preventing the fishing line from being broken when pulled with a strong force or suddenly. For example, Japanese Patent Disclosure No. 11-196731 discloses such a reel. This reel is given a braking force such that when the fishing line is pulled with a strong force in excess of the braking force, the fishing line is rewound-while being under a predetermined tension. The fishing line tension can be freely preset by controlling the braking force provided to the reel, and it is usually preset to about 20 to 30% of the break-strength of the Wishing line.
Still further, by providing a securing member for securing the measuring device to the fishing rod, when the fishing line is pulled suddenly, the tension sensor can provide a buffering effect to protect the fishing line.