A dental treating apparatus has a head unit having a holder for drivably holding a cutting tool, a hand piece body connected to the head unit for transmitting power to drive the cutting tool, and a controller for controlling the driving of the cutting tool. The dental treating apparatus further has a conductive body disposed in an inside of the hand piece body for transmitting an electric signal, contact members electrically connecting the cutting tool or the holder with the conductive body, a connection failure detector for applying a predetermined input signal to the conductive body and detecting a connection failure of the contact members based on a response to the input signal obtained via the cutting tool, and a notifier for notifying a user based on the detection result of the connection failure detector.
