A device state control method for use in an information processing apparatus that has a body, a device connectable to the body, a storage portion which stores information of a state of power supply to the device, the device state control method including: determining whether the information of state of power supply stored in the storage portion is information of power-supply OFF state or not, after instructing to shift the state of the power supply to the device from the power-supply OFF state into a power-supply ON state; and starting the power supply to the device, when the information of power-supply OFF state is stored in the storage portion.