The utility model discloses a fastener dismouting spanner, including a holding the rod, it is hollow tubulose, the pendulum rod, it hinges in a holding the rod's one end, ratchet, it is located a holding the rod's the other end and is equipped with the bayonet socket that can block the fastener, act as go -between, its one end is connected on ratchet, and the other end is connected with the pendulum rod after passing a holding the rod to make ratchet do the motion of intermittent type formula syntropy through the pendulum rod. The utility model discloses a set up pendulum rod and ratchet through acting as go -between and connecting respectively at a holding the rod's both ends, make the bayonet socket on the ratchet carry out the dismouting operation to the fastener, the design is reliable in structure, operations are convenient and flexible, can break away from in maintenance and production process on the one hand, owing to receive operation space limitation to make the puzzlement of dismouting fastener smoothly of ordinary spanner, on the other hand has still effectively solved because the limited dismouting difficulty that leads to the fact in operating personnel work body position, therefore adaptable all kinds of complex environment.