A mobile communication terminal (the mobile station 100), served in a mobile communication network for performing wireless communications, comprises a transmitter-receiver 110, a controller 120, a user interface 130, a data input/output terminal 140, a magnetic writer 150, and a magnetic stripe 160. Control programs stored in a program ROM 122 include a program for controlling the magnetic writer such as writes or deletes various information into/from the magnetic stripe 160. In a credit card ROM 123 are stored information on the attributes of a credit card contract concluded in advance between a user and a credit card company. The magnetic writer 150 writes credit card contract information provided from the controller 120 to the magnetic stripe 160 or deletes the credit card contract information from the magnetic stripe 160.