A remote startup system includes a terminal of a user, a center server that is configured to communicate with the terminal, and a vehicle that is configured to communicate with the center server, and starts up an engine of the vehicle according to a startup request transmitted from the terminal to the center server. The remote startup system includes a lock information acquisition unit configured to acquire lock information indicating whether or not the vehicle is locked when the startup request is transmitted from the terminal to the center server or when a function of transmitting the startup request that is included in the terminal is activated, and a controller configured to change a startup manner of the engine based on the startup request according to whether the lock information indicates that the vehicle is locked or indicates that the vehicle is unlocked.