PURPOSE: To obtain information to show whereabouts corresponding to personal identification data by retrieving a storing means to store the personal identification data and the information to show the whereabouts when the personal identification data of a person whose whereabouts is wanted to know is inputted.

CONSTITUTION: An IC card 1 given an ID number as the personal identification data is issued to each member from a host side. When the member registers that he is staying in a room, he inserts the card 1 into a card reader 3aW3h provided in every room. When the wording of a telegram to show the stay is sent from one of the card readers 3, a computer 2 stores the ID number and a code to show the whereabouts in a control file 4. When the member is searched, after inputting the ID number of the person whose whereabouts is wanted to know by operating the keyboard of the card 1, the card 1 is inserted in the card reader 3. The computer 2 finds out the whereabouts by referring to the file 4, and sends a message. The message is displayed on the display of the card 1.