PURPOSE: To surely prevent dishonesty in relation to medal input by installing between a medal input opening and a medal blocker a medal passing direction detecting device for detecting the passing direction of a medal flowing down in a medal flow-down member.

CONSTITUTION: This inputted medal detecting device 10 is provided with a medal flow-down member 30 in which a medal M inputted from a medal input port 20 flows down, and a medal counting device 40 disposed at a middle length part of the medal flow-down member 30 for counting flowing down medals. It is also provided with a medal passing direction detecting device 60 composed of optical sensors 61, 62 juxtaposed along the flow-down direction of the medal M and positioned between a medal blocker 50 for switching the flow-down direction of the flowing down medal M to discharge the medal M to the outside of a machine and the medal input port 20. When the medal M is inputted, an operation state detected by the detecting device 60 is compared with a regular operation state and in the case of a behavior other than the regular operation state, a dishonest action is judged to have been conducted.