To provide an interference preventing apparatus for a construction machine, which can protect a driving cab from interference of a working machine while ensuring the operational ease of the working machine.

According to the interference preventing apparatus, a speed reduction area in which speed reduction of the working machine 4 takes place, an alarm area in which an alarm is issued, and a stopping area in which the working machine 4 is stopped are set about the driving cab 5, and an outer boundary of the alarm area is set inside an outer boundary of the speed reduction area. Therefore, when a specific portion (a front end of a bucket 8) of the working machine 4 approaches the driving cab 5 and enters the speed reduction area, insofar as the location of the specific portion is outside the alarm area, the alarm is not issued but only speed reduction of the working machine 4 takes place.