A spool brake device for a fishing reel includes an electric spool brake, a rotation detector, and a controller. The rotation detector detects a rotation of the spool. The controller calculates a rotational velocity of the spool based on the rotation of the spool, determines whether the fishing reel is in a casting state based on the rotational velocity, controls the spool brake to brake the spool upon a determination that the fishing reel is in the casting state, and controls the spool brake to not brake the spool upon a determination that the fshing reel is not in the casting state.