The utility model discloses a special tool for replacing a spring of a circuit breaker. The special tool comprises a movable screw rod, an upper internal thread sleeve and a lower internal thread sleeve, the upper part of the movable screw rod is provided with a left-hand thread, and the lower part is provided with a right-hand thread; the upper internal thread sleeve is provided with an internalthread matched with a left-hand thread at the upper part of the movable screw rod and is in threaded connection with the upper part of the movable screw rod; the lower internal thread sleeve is provided with an internal thread matched with a right-hand thread at the lower part of the movable screw rod and is in threaded connection with the lower part of the movable screw rod; the outer wall of theupper internal thread sleeve and the outer wall of the lower internal thread sleeve are each provided with a fixing supporting claw capable of being clamped on a spring. The spring dismounting deviceis simple in structure, easy to manufacture and convenient to operate, can replace manual operation in a narrow space, can finish dismounting or mounting of the spring only by one person, is time-saving and labor-saving, can effectively improve the replacement efficiency of the breaker spring, and has the advantages of being stable in guiding, good in safety, convenient to hold and convenient toapply force.