To provide a coin counting machine capable of shortening the coin counting time, preventing the occurrence of erroneous coin sorting and jamming of coins and discriminating the authenticity of coins at the time of sorting coins.

This coin counting machine is provided with a thickness control gate 4 with an inlet having a size slightly smaller than the double thickness of the thinnest coin among proper coins and a thickness sensor 10 which measures the thickness of a coin 20 while the coin 20 is transported on a transporting path 2 by means of a displacement sensor. When the deformation of the coin 20 is not detected as a result of thickness measurement performed on the coin 20 and the obtained data matched with the data of a proper coin, the machine continues coin sorting operations on the assumption that the coin 20 is a proper one. When the deformation is detected or the obtained data are not matched with the data of the proper coin, the machine immediately discriminates the coin 20 as a forged coin and ejects the coin 20 to the outside.