a hopper device has an insulating hopper member . a first electrode is mounted in the inner side of the hopper member in a lowermost portion thereof , and at least one second electrode is mounted in the inner side of the hopper member in a portion thereof at a higher level than the first electrode . when coins having conductivity are collected in the hopper member until their level reaches the second electrode , the first and second electrodes are electrically coupled together by the coins , whereby an electric signal representing the amount of collected coins is generated .