PURPOSE: To obtain a tackling-changing device capable of automatically and surely changing from a fixed float tackle to a freely floating tackle even by an angler lack of high technique and rich experience.

CONSTITUTION: This changing device is composed of a spool S to be slidably engaged with a fishing line L, fixed bearing cases C1, C2 to rotatably support the spool S and spool braking mechanisms B placed between the spool S and each of the fixed bearing cases C1, C2. When the spool S is turned by a definite angle (θ) from outside of the fixed bearing cases C1, C2, the fishing line L is wound on the spool in an unslidable manner and the spool S is fixed and locked by the braking mechanism B. When a prescribed definite tension is applied to the fishing line L, the spool S is automatically rotated in reverse direction.