The invention provides a scanning device, a scanning machine and a motor assembling production line relating to the technical field of automation production. The scanning device provided by the invention comprises a scanner, a reflector and a reflector adjusting mechanism; the reflector adjusting mechanism comprises a fixing seat, a rotating member and a locking member; the fixing seat is mountedunder a workpiece to be scanned; the reflector is mounted on the rotating member; the reflector is disposed obliquely with respect to the horizontal plane; the rotating member is rotatably connected to the fixing seat for driving the reflector to rotate relative to a production line body to adjust the tilt angle of the reflector so as to enable reflected rays shooting downwardly toward the reflector in a vertical direction to diffuse to the scanning device; and the locking member is used to lock the rotating member to the fixing seat. Through the scanning device provided by the invention, thetechnical problems that when downward identification codes on a workpiece is scanned, the code scanning identification apparatus is relatively difficult to install and the identification code is difficult to scan are solved.