There is provided a mobile communication device having a function capable of releasing lock on an IC card function by an authentication key other then a PIN if the IC card function is locked by a PIN authentication error in a mobile phone having a contactless IC card built in. When a PIN is locked in a mobile phone 1 having a contactless IC card built in, an IC application 11 is started up to transmit a second password other than a PIN to an authentication server 3. The authentication server 3 compares the second password received from the mobile phone 1 with another second password stored in a database 31. If both second passwords agree with each other, a PIN lock release command is transmitted to the mobile phone 1. Further, the mobile phone 1 switches the lock flag of the contactless IC card 13 to OFF from ON by the command received. The PIN lock of the IC card function is thereby released.