money-changing machine; currency exchange machine
A machine that exchanges bills for coins, or one currency for another. Commonly found in banks, airports, and arcades.
I exchanged dollars for yen at the airport currency exchange machine.
I change a 1,000-yen bill into 100-yen coins at the arcade's change machine.
Compound of 両替 (りょうがえ, 'money exchange') + 機 (き, 'machine').