PURPOSE: To use a small-size reader/writer for a magnetic memory card and handle the card in an easy manner by a method wherein a light reflection surface part characterized by an intrinsic reflection direction which can be identified by an optical identifying means is provided near a magnetic stripe.

CONSTITUTION: On a card reader/writer 2, a slot 5 is provided for passing a part of a card 1 containing a magnetic stripe 3 and an area 1a. In the card reader/writer 2, a magnetic head 6 is provided so as to face the slot 5 for transmitting data to/from the magnetic stripe 3. On a position upstream of the magnetic head 6 in the feed direction of the card 1, a light emitting element 7 is provided so as to face the slot 5 as a means for emitting an illuminating light of laser light toward a hologram part 4, thereby identifying the hologram part 4 whether the card 1 is normal.