To provide a spool-braking device in a reel for fishing, capable of corresponding to rapid change of circumstances, providing improved flying distance of a device, and having improved operability of winding a fishline, and the like by reducing unnecessary braking.

This spool-braking device in the reel for the fishing is obtained by arranging an electromagnet so as to face to an electric conductor rotating so as to synchronize with the rotation of the spool to magnetically brake the rotation of the spool when releasing the fishline by the eddy current generated in the electric conductor. The device has a rotation-detecting means for detecting the number and the direction of the rotation of the spool, a memory having a previously set and memorized, prescribed value according to the rotative speed of the spool, and a controlling means for controlling the energizing of the electromagnet. The controlling means controls the energizing of the electromagnet according to the prescribed value based on the rotative speed of the spool at actual fishing calculated from a detected value by the rotation-detecting device to control the magnetism of the electromagnet.