A detection system according to the present invention includes a control device that detects fraud conducted on a game table by using the image analysis result obtained by an image analysis device. In addition, each game token used in this detection system has a multilayer structure having plastic layers with a plurality of different colors stacked on each other, with a colored layer being provided at least intermediately, and white layers or light-colored layers (not illustrated, but may be any layers lighter in color than the colored layer) being stacked on two sides of the intermediate colored layer. As described above, this game token has a multi-layer structure including the colored layer, with the white layers or light-colored layers (not illustrated, but may be any layers lighter in color than the colored layer) being stacked on the two sides of the intermediate colored layer.