A power tool, comprising: a housing; a motor being disposed in the housing for outputting rotary power; an output shaft having an accommodating hole in the axial direction for holding a tool bit; a transmission mechanism, being disposed between the motor and the output shaft for transmitting rotary power from the motor to the output shaft; a tool bit supporting being disposed in the housing and including several chambers disposed in parallel for holding the tool bit; a connecting member being disposed in the housing and capable of moving axially between a working position where the connecting member passes through one of the chambers and to accommodate the tool bit in the chamber connect the output shaft, and a release position where the connecting member exits and separates from one of the several chambers; and an operating member is arranged on the housing for controlling the axial movement of the connecting member; the power tool further includes an automatic shifting means for adjusting the position of the tool bit supporting in response to the movement of the operating member, wherein the connecting member moves axially to a position that is separated from one of the several chambers, and the cartridge moves to a position where another chamber is axially corresponding to the output shaft under the action of the automatic shifting means.