<p>There is provided an information recording device for recording record information onto an information recording medium having a plurality of recording layers. The information recording device includes: write means capable of writing record information into the recording layers; control means for controlling the write means to write first boundary information or second boundary information (107a-0) having a smaller recording capacity than the first boundary information at the end of record information recorded in one of the recording layers; and detection means for detecting an empty capacity of the data area in that recording layer. The control means controls the write means to write the first boundary information at the end if the empty capacity is equal to or greater than a first threshold value and the second boundary information at the end if the detected empty capacity is smaller than the first threshold value.</p>