To provide a Pachinko game system for easily finding a fraudulent action to prevent the subtraction of the balance of a prepaid recording medium by forcibly changing the signal level of a ball dispensing completion signal to be transmitted from a Pachinko game machine to a prepaid recording medium reader.

When the put-out of dispensed balls is completed, the put-out control board 60 of the Pachinko game machine 1 transmits a ball dispensing completion signal EXS, having a specific duty ratio as the duty ratio (tb/ta) between a time ta to be changed into a high level and a time tb to be changed into a low level in the one cycle of the signal, to the prepaid recording medium reader 100. The CPU 121 of the prepaid recording medium reader 100 calculates the duty ratio of the received ball dispensing completion signal EXS (S9), and when the duty ratio is not within the range of a regulation value (S10: No), performs an error notification (S12).