Abstract: An information recording medium such as DVD-R, DVD-RW or the like is provided with a user information recording area in which user information can be recorded. The user information recording area has pre-recorded areas for preventing recording/reproduction of the user information, in a plurality of portions. The user information recording area is divided by the pre-recorded areas into a plurality of partial recording areas including a partial recording area smaller than a unit area in which record information of a read-only recording medium is recorded.