A spool brake device (25) for a dual-bearing reel according to a first aspect of the present invention is a device configured to electrically brake a spool (12) rotatably mounted to a reel unit (1) of the dual-bearing reel for allowing a fishing line to be wound thereabout. The spool brake device (25) includes a spool brake unit (40) including a magnet (61) configured to rotate in conjunction with rotation of the spool (12), and a coil (62) configured opposite to the magnet (61) to generate electric current with rotation of the magnet (61), a tension detecting unit (82) configured to detect and measure tension on the fishing line, and a spool control unit (42) configured to control the spool brake unit (40) by analog-controlling electric current flowing through the coil (62) on the basis of how large the tension is.
