A communication game system for a competitive communicative driving game. Preliminary races are actually conducted for each client system in a single-vehicle driving style in accordance with operations by players, and qualifiers who are highly ranked according to their finishing times are selected (S1 to S10). The final races (S12) are set for the qualifiers. Also in the final races, the final races are actually conducted for each client in a single-vehicle driving style in accordance with operations by the players, and the driving data is then transmitted to the server (S11 to S14). The server processes the driving data obtained from each client and returns the processing results to each client (S14). After the network is disconnected, the processing results are reproduced and displayed as replay images at each client (S15 and S16).