This paper presents "On-line AR Baseball Presentation System", which is a vision-based AR application for entertainment. In this system, a user can watch a virtual baseball game scene on a real baseball field model placed on a tabletop through a web-camera attached to a hand-held LCD monitor. The virtual baseball scene is synthesized from an input history data of an actual baseball game. Visualizing the input history data can help the user to understand the contents of the game. For aligning the coordinate of the virtual baseball game scene with the coordinate of the real field model, we use multiple planar markers manually distributed into the real field model. In contrast with most of AR approaches using multiple markers, we do not need any manual measurement of the geometrical relationship of the markers, so that the user can easily started and enjoy this system.