PURPOSE: To provide a game medium grinding device with simple constitution and capable of drastically reducing cost, effectively using a space in a game machine island as far as possible and maintaining grinding capacity for a long period without mixing an abrasive material.

CONSTITUTION: This game medium grinding device 30 is arranged so as to be connected in the longitudinal direction mutually, and formed by arranging side by side a pair of conveyers 31a, 31b in parallel in the vertical direction by taking an interval to narrow a game medium between carrier belts 32 for them, and each terminal part on the same side of the pair of conveyers 31a, 31b is connected so as to be adjusted and fixed, and at least the carrier belt 32 on one side out of the conveyers 31a, 31b is formed with the abrasive material. Also, an island middle stage 20B is formed so as to extend plural game machines 21 set back to back in a lateral direction in a state that they are oppositely equipped mutually without interposing another game relational facility between the backs of them.