The invention discloses a cutting gun anti-collision device of a cutting machine, and relates to a mechanical cutting device. The device comprises a rolling body assembly, a cutting gun clamping assembly, buffer assemblies and an anti-collision device fixing support; the relation position of a cutting gun head and rolling bodies are kept unchangeable all the time, and the rolling bodies are in tight contact with a steel plate all the time; the relative motion of the rolling bodies and the steel plate is rolling motion; in the cutting process, when the steel plate deforms, rapid response can be achieved; and the optimal cutting height of a cutting gun can be kept all the time; in the cutting process, when the steel plate deforms and protrudes, the rolling bodies can rapidly respond to, displacement can be rapidly transmitted to the cutting gun, finally, the cutting gun head avoids the protruding position of the steel plate, and collision of the cutting gun is prevented; and no matter whether the steel plate deforms and protrudes or deforms and sinks, the optimal cutting height of the cutting gun relative to the steel plate is always kept.