To provide a transaction monitoring device which prevents fraud damage, and prevents smooth money transaction between legal users from being hindered in the case of performing money transfer processing between users by an automatic transaction apparatus.

The monitoring device for monitoring the user of the automatic transaction apparatus capable of performing a transfer processing includes: a portable telephone use detection means for detecting the use act of the portable telephone of the user; an age detection means for detecting that the user is over a prescribed age; and an abnormality detection means for detecting the use of the portable telephone of the user who is performing the procedure of the transfer processing, and for, when it is detected that the age of the user is over the prescribed age, notifying the user of a warning.