A medical electric tool has a grip portion and a driving portion. The grip portion has a combining protrusion, two combining channels, and a locking device. The combining channels are defined respectively in two sides of the combining protrusion. The locking device is mounted in the combining protrusion and has two locking blocks and two recoil springs. Each locking block has an engaging segment. The engaging segment is formed on one end of the locking block and extends into one of the combining channels. The driving portion is detachably mounted on the combining protrusion on the grip portion and has a bottom face and two engaging ribs. Each engaging rib has an end provided with an engaging hook selectively engaging with the engaging segment of a corresponding one of the locking blocks.
