To provide a dangerous object detecting device for construction equipment, which notifies an operator and the dangerous object when the object is detected in a predetermined range from a machine body, and facilitates analysis of an accident cause in the case of an accident, to thereby prevent recurrence of the accident.

According to the construction equipment, an ultrasonic sensor 17 for detecting the object existing in the predetermined range Z from the machine body, is arranged at a predetermined location of a revolving super structure 12, and a worker 18 carries with him a transponder 19 for responding to radio waves transmitted from the ultrasonic sensor 17. When the worker 18 enters the predetermined range Z, the transponder 19 carried with him responds to the radio waves at a predetermined frequency transmitted from the ultrasonic sensor 17, and transmits radio waves at a specific frequency again. When the ultrasonic sensor 17 receives the radio waves at the specific frequency, it outputs a detection signal. Then a control device 20 outputs an activating signal to an alarm display device 21 to notify the operator and the worker 18 of danger, and records an operating condition of the ultrasonic sensor 17 and a working condition of the construction equipment, in an alarm recording device 22.