A spool braking device for a dual bearing reel includes a spool brake unit, a spool control unit, and a tension detection unit that includes a rotational speed sensor. The spool control unit is arranged between a spool and a reel body, and it an electrically controllable unit that controls the spool. The tension detection unit detects the tension applied to fishing line that is released from the spool during casting. The spool control unit electrically controls the spool braking unit so that the spool braking unit brakes the spool with a first braking force of 50 to 100% of the maximum braking force during a first predetermined time period when the tension detected by the tension detection unit is at or below a first predetermined value.