A multi-unit coin ejection apparatus comprising: a base having a mounting surface; coin ejection units mounted on the mounting surface, each of the coin ejection units having a rotary disk; a first motor commonly used for driving the coin ejection units; a driving mechanism that is configured to drive the coin ejection units by transmitting a driving force of the first motor using gears; a switching unit that is configured to switch a destination of the driving force of the first motor, thereby selectively driving a desired one of the rotary disks of the coin ejection units; and an unnecessary rotation prevention mechanism, provided in each of the coin ejection units, that is configured to prevent unnecessary normal rotation of a corresponding one of the rotary disks of the coin ejection units; wherein the switching unit comprises (i) first coupling gears which are respectively provided for the coin ejection units, (ii) second coupling gears which are engageable with the corresponding first coupling gears and which are provided for the driving mechanism, and (iii) a coupling gear displacement mechanism that is configured to displace the second coupling gears between a coupling position and a non-coupling position; the coupling gear displacement mechanism is operated in response to an instruction in such a way that a designated one of the coin ejection units is placed in a driving state where a designated one of the second coupling gears is disposed at the coupling position and that a remainder of the coin ejection units is/are placed in a non-driving state where a remainder of the second coupling gears is/are disposed at the non- coupling position; the unnecessary rotation prevention mechanism comprises an unnecessary rotation prevention member that is formed to prevent the relevant rotary disk from normally rotating to result in incorrect coin ejection when the relevant coin ejection unit is placed in the non-driving state; the unnecessary rotation prevention member is structured in such a way as to be engaged with the relevant first coupling gear or disengaged therefrom in response to displacement of the relevant second coupling gear between the coupling position and the non-coupling position; when the relevant coin ejection unit is placed in the non-driving state, an engaging or engaged part of the unnecessary rotation prevention member is engaged with one or more engaged or engaging parts of the relevant first coupling gear, thereby preventing normal rotation of the relevant rotary disk; and when the relevant coin ejection unit is placed in the driving state, the engaging or engaged part of the unnecessary rotation prevention member is disengaged from the one or more engaged or engaging parts of the relevant first coupling gear, thereby permitting normal rotation and reverse rotation of the relevant rotary disk. a base having a mounting surface; coin ejection units mounted on the mounting surface, each of the coin ejection units having a rotary disk; a first motor commonly used for driving the coin ejection units; a driving mechanism that is configured to drive the coin ejection units by transmitting a driving force of the first motor using gears; a switching unit that is configured to switch a destination of the driving force of the first motor, thereby selectively driving a desired one of the rotary disks of the coin ejection units; and an unnecessary rotation prevention mechanism, provided in each of the coin ejection units, that is configured to prevent unnecessary normal rotation of a corresponding one of the rotary disks of the coin ejection units; wherein the switching unit comprises (i) first coupling gears which are respectively provided for the coin ejection units, (ii) second coupling gears which are engageable with the corresponding first coupling gears and which are provided for the driving mechanism, and (iii) a coupling gear displacement mechanism that is configured to displace the second coupling gears between a coupling position and a non-coupling position; the coupling gear displacement mechanism is operated in response to an instruction in such a way that a designated one of the coin ejection units is placed in a driving state where a designated one of the second coupling gears is disposed at the coupling position and that a remainder of the coin ejection units is/are placed in a non-driving state where a remainder of the second coupling gears is/are disposed at the non- coupling position; the unnecessary rotation prevention mechanism comprises an unnecessary rotation prevention member that is formed to prevent the relevant rotary disk from normally rotating to result in incorrect coin ejection when the relevant coin ejection unit is placed in the non-driving state; the unnecessary rotation prevention member is structured in such a way as to be engaged with the relevant first coupling gear or disengaged therefrom in response to displacement of the relevant second coupling gear between the coupling position and the non-coupling position; when the relevant coin ejection unit is placed in the non-driving state, an engaging or engaged part of the unnecessary rotation prevention member is engaged with one or more engaged or engaging parts of the relevant first coupling gear, thereby preventing normal rotation of the relevant rotary disk; and when the relevant coin ejection unit is placed in the driving state, the engaging or engaged part of the unnecessary rotation prevention member is disengaged from the one or more engaged or engaging parts of the relevant first coupling gear, thereby permitting normal rotation and reverse rotation of the relevant rotary disk.