To perform post-recording including sound monitoring (while reproducing sound) by using a device which cannot execute simultaneous sound coding/decoding.

This recording device temporarily records post-recording signals in a format (with light processing load) different from the standard post-recording format. Later, it converts the signals into the standard format after the post-recording, or converts it into the standard format by simplifying the processing in the decoder (coding while the decoder is sleeping), or to decide the post-recording mode (with sound monitor, without sound monitor, or no post-recording) depending on the remaining quantity of the recording medium.