Provided is a snowboard binding in which a stopper function operates when a boot is removed and the stopper function is released when a boot is mounted, and a stopper device for a snowboard binding that can be attached to and used in a binding of a type exemplified in Patent Document 1. A snowboard binding configured so as to be provided with an urging body (9) for rotatably urging a highback (4) rearward, and configured so that when a lock lever (7) of a lock mechanism (6) is placed in an unlocked state by the rotational urging of the urging body (9), the highback (4) automatically rotates rearward, and configured so that when the highback (4) arrives at the rearward-rotation-limit position or near the rearward-rotation-limit position, a connecting cord (8) of the lock mechanism (6) is tensioned, the orientation in which the lock lever (7) projects from the highback (4) rear surface section is maintained, and the lock lever (7) in this projecting orientation makes contact with the snow surface (S) below a snowboard (1) to bring about a slide-preventing effect.