A data-overwriting technique that facilitates determining whether data is new or old. A tape recording apparatus includes: a receiving unit for receiving information on overwrite starting position and an overwrite request; a trying unit for trying to determine a beginning position of a data unit; an overwrite executing unit for executing overwriting from the determined overwrite starting position in response to a success of the determination by the trying unit; and a type judging unit for judging whether the data unit that is recorded at the overwrite starting position is a null data unit or not in response to a failure of the determination by the trying unit. The trying unit responds to judgment that the data unit is the null data unit by determining a beginning of a data unit following the data unit as the overwrite starting position.