To provide a game ball dispenser lending the game balls used by a player when playing a game on a game machine and capable of detecting the fraudulent delivery of game balls and to provide a fraud detecting device adapted to the existing game ball dispenser, capable of detecting the fraudulent delivery of game balls, and easy to fit at a low cost.

This game ball dispenser 1 is provided with a game ball storage hopper 11 storing game balls Cos, a game ball delivering device 12 delivering the game balls Cos, a money detecting device 13 detecting the money inserted by the player and instructing the game ball delivering device 12 to output a lending signal a1 for the delivery of the game balls Cos, a delivery action signal output device 14 outputting a delivery action signal b1, a fraud detection signal forming device 15 capable of forming a fraud detection lending signal a2 based on the lending signal a1 when receiving the lending signal a1 and capable of forming a fraud detection delivery action signal b2 based on the delivery action signal b1 when receiving the delivery action signal b1, a fraud presence judging device 16 judging the presence or absence of the fraudulent delivery of game balls based on the signal state formed by the fraud detection signal forming device 15, and a fraud determining device 4.