To prevent a trouble which occurs with a user at the time of abnormality on the card side by constituting an automatic teller machine so as to issue alarm to the user at the time when there is a problem in the recording state of a card.

When a user inserts the card in an inserting/ejecting port, a waveform reshaping circuit 34 reshapes the waveform of a reading signal outputted from a magnetic head 18 with a prescribed setting level. A card reader control CPU 35 measures the writing record density and the reproduction output level of information which is recorded in the card based on the signal which is reshaped by the waveform reshaping circuit 34. The two kinds of data are transferred to a mainbody main control part 10 with a unit control part 16 at need, executed a graphic processing and displayed on the screen of a touch pannel display device 12. Thus, the user can easily know whether or not abnormality exists in his own card by viewing a reproduction output graph equivalent and/or a jitter graph equivalent displayed on the screen.