A probe unit for an electro-surgical device to apply high level frequency voltage to an operating area, the probe unit including an operative end portion provided with a forward cutting tip, and a rear housing connector portion provided with a ferrule rotatably connected to the remaining body portion thereof, a rear end of the operative end portion being threadingly engaged with the ferrule for rotation therewith and for easy removal thereof so that the operative end portion can be sterilized and then re-engaged onto the ferrule of the rear housing connector portion. The operative end portion has an elongated length considerably longer than the rear housing connector portion to prevent cross-contamination of a user and/or patient when the probe unit is being used. The body of the operative end portion is tapered with a rear enlarged portion thereof being provided with laterally extending fins thereabout to provide for uniform curing and a uniform cross-section thereof. The body portion of the rear housing connector portion is provided with lamps to indicate when the high level frequency voltage is being applied at the cutting tip. In one modified embodiment, the operative end portion includes an on/off switch, and in another modified embodiment, the operative end portion is provided with a releasable wedge connecting engagement to permit the replacement of the cutting tip.