To realize a voice recorder which is suitable for taking voice notes and easier to use.

(1) Inputted voice data are stored together with their storage time and the distribution of the storage time is displayed. (2) Whether the voice data are reproduced is stored and the presence of voice data which are not reproduced yet is reported to a user to attract user's attention. (3) A radio wave including the standard time is received to obtain the standard time, which is embedded in the voice data so that alteration can be detected to indicate that the voice data were already present at the time and also stored, thereby increasing the evidence capability of the voice data.