Optical touch panel and automatic vending machine

An automatic vending machine comprising a optical touch panel including:

• a pair of retroreflective plates that are arranged inside at least a left and right pair of frame portions facing each other in a rectangular frame;
• a plurality of detectors that are arranged at four corners of the rectangular frame, the detectors being configured to irradiate infrared rays to, at least, the retroreflective plates, and to generate detection images based on reflection light from the retroreflective plates;
• and
• an operation determining unit configured to detect a touch position based on the detection images generated by the detectors, the optical touch panel being arranged on an external door of the automatic vending machine.