An apparatus records main information and sub information onto an information recording medium, which has a main recording area and a sub recording area. The apparatus is provided with an receiving device that receives the main information input from the external source; an accumulating device that accumulates the main information received by the receiving device; a recording device that records the main information and the sub information to the main recording area and the sub recording area, respectively; and a controller that determines whether or not an amount of the main information accumulated in the accumulating device is smaller than a predetermined amount, and that controls the recording device. In the apparatus, the recording device records the sub information to the sub recording area under a control of the controller if the controller determines that the amount of the main information accumulated in the accumulating device is smaller than the predetermined amount, and the recording device records the main information to the main recording area under a control of the controller if the controller determines that the amount of the main information accumulated in the accumulating device is not smaller than the predetermined amount.