The invention discloses a sanding machine which comprises a motor provided with or connected with a driving shaft, a housing for accommodating the motor, a base plate driven by the driving shaft and aclamping part matched with the base plate to clamp sanding paper. The clamping part comprises a clamping portion in contact with the sanding paper, a rotary shaft portion in rotary connection with the base plate and a combining portion combined with the base plate to make a part of the clamping portion and a part of base plate clamp the sanding paper from two sides. A clamping face matched with the clamping portion is formed on the base plate. The ratio of the distance from the clamping face to the rotary axis of the rotary shaft portion to the maximum size of its rotary axis in the radial direction is greater than 0 or smaller than or equal to 4. The sanding machine is stable in sanding paper clamping, and the base plate is not likely to deform.