Drag adjustment knob adjusts the braking force applied to a spool mounted on a spool shaft that has a single-thread first male screw on its front end. The drag adjustment knob includes first and second adjustment units, a transmission unit, and a pressing unit. The first adjustment unit includes a first female screw that screws onto the first male screw. The transmission unit is non-rotatably but axially movably mounted onto the spool shaft to be in contact with the first adjustment unit, and includes a multi-thread second male screw. The second adjustment unit includes a second female screw, which screws onto the second male screw and has a greater screw lead than that of the first female screw. The pressing unit is disposed between the second adjustment unit and the drag mechanism so as to come into contact with both, and is non-rotatable but axially movable with the spool shaft.