According to one embodiment, there is provided an optical disk apparatus including a recording unit which irradiates an optical disk with a laser beam to record information in a first format and a second format, a generation unit which generates warning information to an optical disk apparatus capable of performing a read process in the second format while being not capable of performing the read process in the first format, the warning information warning that information is recorded in the first format in the optical disk, and a control unit which controls the recording unit to record the warning information in the second format in the optical disk apparatus when the information is recorded in the first format in the optical disk.