Recently, cloud gaming services are emerging. Cloud gaming is instant gaming without installing the games in the devices of players. All computation in cloud gaming is done by dedicated servers, then the rendered game frames are sent to the players. Scalability is a serious problem in cloud gaming. To make a cloud gaming server accommodate more users, we must reduce the total amount of computation and memory. In a game, many objects are duplicated among users and users watch the same game scene just in different angles. Therefore, we can share computation and memory except the parts related to the camera view. We coined this technique as game sharing. In this thesis, we proved that game sharing can resolve the scalability problem by applying it to DirectX samples. The evaluation results show that the scalability can be improved about 3 times better using game sharing technique.