Disclosed in the present invention is a quick-replacement gun type bolt tightening device. An electric motor is fixed in a main shaft shell, a motor output shaft of the electric motor is in transmission connection with a bolt tightening device ferrule through a transmission shaft, the bolt tightening device ferrule is rotationally connected to a vertical plate, the vertical plate is fixedly connected to a front end of the main shaft shell, a bolt tightening device rolling wheel is arranged between the main shaft shell and the vertical plate, the bolt tightening device rolling wheel is rotationally connected to the transmission shaft, the bolt tightening device rolling wheel is provided with a plurality of bolt tightening device storing through holes, one bolt tightening device unit is placed in each bolt tightening device storing through hole, a bolt tightening device pushing and pulling device is arranged in the main shaft shell, a handgrip is fixed to a rear side of the bottom of the main shaft shell, a battery is fixed in the handgrip, and a button used for controlling the electric motor to rotate is arranged in front of the handgrip. As can be seen from the structure, the quick-replacement gun type bolt tightening device realizes the quick replacement of the bolt tightening device unit, and the operation efficiency is improved.