This paper presents the methods of dynamic load-balancing and control, which are applied for server-side rendering on Ajax-GIS. Ajax-GIS uses divided raster image tiles called for “tile” in order to keep light handling on web browser without some additional plug-in software. Server-side rendering is a technique for drawing images on the server side, which is effective to be able to solve the cross-browser issues and to reduce the client load. However when many clients request the Ajax-GIS server to render tile images, the server load will increase. In order to this issue, we propose the dynamic load-balancing and control by means of estimating server-side rendering request and monitoring server load. In experiments and evaluations of our proposed methods making use of an actual map data, we confirmed the effectiveness of our methods as comparing with conventional methods.