A slack correction mechanism comprising: a distal-end pulley that is rotatable with respect to a given axis; a distal-end wire wound around the distal-end pulley; a first supporting part including a first base, a first friction portion which extends out from the first base and around which the distal-end wire wound around the distal-end pulley is looped on one side and a first biasing portion that biases the distal-end wire in a pulling direction on one end side with respect to the first friction portion, the first supporting part being adapted to support one side of the distal-end wire; and a second supporting part including a second base, a second friction portion which extends out from the second base and around which the distal-end wire wound around the distal-end pulley is looped on the other side and a second biasing portion that biases the distal-end wire in a pulling direction on the other side with respect to the second friction portion, the second supporting part being adapted to support the other side of the distal-end wire, characterized by an interlocking part activated such that when one of the first supporting part and the second supporting part moves in a pulling direction of the distal-end wire, the other moves in a delivery direction of the distal-end wire, a driving unit for driving the interlocking part; and an operating unit that is put by an operator in operation to drive the driving unit, wherein the interlocking part includes an interlocking pulley having a movable axis, and an interlocking wire wound around the interlocking pulley, and fixed at one end to the first base and at the other end to the second base. a distal-end pulley that is rotatable with respect to a given axis; a distal-end wire wound around the distal-end pulley; a first supporting part including a first base, a first friction portion which extends out from the first base and around which the distal-end wire wound around the distal-end pulley is looped on one side and a first biasing portion that biases the distal-end wire in a pulling direction on one end side with respect to the first friction portion, the first supporting part being adapted to support one side of the distal-end wire; and a second supporting part including a second base, a second friction portion which extends out from the second base and around which the distal-end wire wound around the distal-end pulley is looped on the other side and a second biasing portion that biases the distal-end wire in a pulling direction on the other side with respect to the second friction portion, the second supporting part being adapted to support the other side of the distal-end wire, characterized by an interlocking part activated such that when one of the first supporting part and the second supporting part moves in a pulling direction of the distal-end wire, the other moves in a delivery direction of the distal-end wire, a driving unit for driving the interlocking part; and an operating unit that is put by an operator in operation to drive the driving unit, wherein the interlocking part includes an interlocking pulley having a movable axis, and an interlocking wire wound around the interlocking pulley, and fixed at one end to the first base and at the other end to the second base.