To provide a scaler which is capable of efficiently cleaning teeth and can be easily manufactured.

The scaler which is formed to an elongated flat planar shape and removes calculi by being inserted between the adjacent teeth 36 and 37 has a handle 2 which can be clamped by the fingertips and a first knife blade 19 which is connected to one end in the longitudinal direction of the handle 2 by means of first and second crooks bent to one side in a thickness direction and is formed with a blade edge 18 at the outer end in the longitudinal direction and therefore the handle is formed to a planar form to enable a user to clamp the scaler by the fingertips and easily to remove the calculi in removing them. The handle is provided with crooks, by which the shape to allow the first knife blade 19 to turn around the rear sides of the teeth is obtained.