To provide a method for easily demounting an upper bead on a flat tire or run-flat tire.

A demount claw 4 forms an outer groove 31 at a higher position and an inner groove 32 at a lower position at the distal end. The demount claw 4 is deformed by pressing near an upper bead part of the tire 21. The upper tire bead 23 is engaged with the outer groove 31. The demount claw 4 is moved upward to engage the inner groove 32 with an end edge 24 of the wheel 20. The upper tire bead 23 is detached by turning the wheel 20 in the above state.