Powder spreading device and 3D metal printer

The utility model provides a powder spreading device and 3D metal printer, the 3D metal printer is provided with an operation chamber, the operation chamber is internally provided with a printing operation platform, the printing operation platform is provided with a forming area, the powder spreading device comprises a feeding bin, a powder spreading assembly and a horizontal moving part, the powder spreading assembly comprises a discharging bin, a spreading roller and a driving mechanism, the height of the discharging bin is lower than that of the feeding bin, and the horizontal moving part is arranged on the horizontal moving part. A feeding port of the discharging bin can be communicated with a discharging port in the bottom of the feeding bin in an opening and closing mode, the laying roller is suspended above the forming area, the roller face of the laying roller is close to the discharging port of the discharging bin, the driving mechanism is used for driving the laying roller to rotate, and the horizon