Provided is a moving mechanism for a blast gun which can easily move a blast gun accommodated in a blasting chamber and which can easily perform other operations from the outside thereof without leaking dust. A plurality of arm members (first input arm 21, second input arm 22, first output arm 31, and second output arm 32) are interlocked to form an input arm 20 and an output arm 30, each having one pair of arm members, one arm of the two arm members is pivotally attached to the other arm so as to be rotatable around an interlocked portion serving as a fulcrum, the input arm 20 is disposed outside the blasting chamber 3, and the output arm 30 is disposed inside the blasting chamber 3. In addition, the input arm 20 and the output arm 30 are interlocked to each other by an interlocking unit 40 which penetrates a top plate of a cabinet 4, and a power transmission mechanism is provided which rotates the second arm 22 synchronously with the rotation of the input arm 20, so that a blast gun 5 fitted to the output arm 30 can be moved by operating the input arm 20.