To make content irreproducible in a recording device after a set expiration time, the recording device has a read/write unit for reading and writing data on a recording unit, the read/write unit having electric power supplied from an external power source, a clock containing a built-in battery, an input/output interface for inputting data from outside and outputting data to outside, and a controller for controlling the read/write unit and the input/output interface. The recording medium includes an ordinary data area for writing ordinary data and an expiration time data area for writing an expiration time of ordinary data. The controller prevents ordinary data written in the ordinary data area from being output to outside when the expiration time written in the expiration time area has passed a time limit calculated by the clock.