An image recognition system includes a first computer for detecting a recognition target from image data, and a second computer for identifying the recognition target detected by the first computer. The first computer and the second computer are disposed at positions physically separated from each other. When the first computer sends image data to the second computer, the second computer sends to the first computer a detection parameter group used for detection via a communication path. The detection parameter group is included in a recognition parameter group that is dynamically changed and used for image recognition processing of the image data.