An operating system startup control method includes the steps of continuing an operation of a program loader for a specific processor among program loaders for the other processors that are started up by turning on of the power supply to the plural processors, while terminating the program loaders for the other processors; starting up an OS bridge that manages a hardware resource shared by the plural processor, using the program loader and starting up an operating system corresponding to the specific processor and another operating system corresponding to the other processors, using the OS bridge that is started up.