To provide a network game system capable of making an information terminal participating in a network game smoothly advance the game without the feeling of incompatibility.

The network game system includes a game server for receiving a main game operation request and a subordinate game operation request transmitted from a main terminal and a subordinate terminal corresponding to a game to be provided. The main terminal reflects an input main game operation request and the subordinate game operation request received from the subordinate terminal through the game server on the game under execution in the own terminal, and transmits the reflected game operation request to the game server. The game server transmits the subordinate game operation request received from the subordinate terminal to the main terminal, and transmits the reflected game operation request received from the main terminal to the subordinate terminal. The subordinate terminal transmits an input subordinate game operation request to the game server, and reflects the reflected game operation request received from the game server on the game under execution in the own terminal.