To provide a work range restriction device of a two stage folding high altitude demolishing machine, which allows high altitude demolishing work and a low altitude demolishing work with safety within a toppling limit working radius in which the stability of the machine in a demolishing work mode is ensured, and allows back hoe work with safety within a toppling limit working radius in which the stability of the machine in a back hoe work mode is ensured in a broader range and to a deeper underground location than that of the low-altitude demolishing work.

The work range restriction device of the two stage folding high altitude demolishing machine has: a demolishing work mode switch 15a for selecting the demolishing work mode when the demolishing machine mounts a crusher 8 thereon; a back hoe work mode switch 15b for selecting the back hoe work mode when the demolishing machine mounts a bucket thereon; a boom angle detection switch 11 for detecting a lowering angle of a boom 5 and restricting the lowering angle to a set lowering angle corresponding to the work mode; and an arm angle detection switch 12 for detecting an open angle of an arm 7 and restricting the open angle to a set open angle corresponding to the work mode.