PURPOSE: To provide an industrial robot collision detecting method and a device thereof that can attain almost constant collision detecting sensitivity regardless of the action speed of an industrial robot.

CONSTITUTION: The increment value DELPOS of the joint angle command value is multiplied by feedback gain KF by a multiplier 1 and passed through a first order lag filter 3 to obtain theoretical position deviation PoserrT. On the basis of this position deviation PoserrT, a threshold setting part 4 sets the upper limit value Ulimit and the lower limit value Llimit. A collision detecting part 5 judges whether or not the position deviation POSERR is out of the range of the upper limit value and lower limit value, and detects a collision in the case of being out of the range.