An injector (100) includes an injection button (111) and a coil (110) for radiating energy that informs an injection button detection device (200) combined with the injector, of an input of the injection button. The injection button detection device (200) includes a transmitter for radiating an electromagnetic wave associated with a specific voltage to radiate energy that informs an injector combined with the injection button detection device, of an input of an injection button a receiver for receiving a voltage based on energy radiated from the injector and a controller for detecting an input of the injection button based on the voltage received from the receiver.
