A parallel computer includes a first processor, a second processor, and a first storage device. The first processor outputs, in response to an instruction for starting up the parallel computer, a first read-out request causing the first storage device to transmit a command of an initialization process to the first processor. The first processor executes the initialization process of the first processor by using the command received from the first storage device. The second processor monitors, in response to the instruction for starting up the parallel computer, a signal transmitted between the first processor and the first storage device. The second processor detects, from the signal monitored, the command output from the first storage device. And, the second processor is configured to execute the initialization process of the second processor by using the detected command.