Herein are disclosed a cable television system, mobile communication terminal, a relay apparatus, a center apparatus, and a method of providing a cable television service using the system, which enable a user operating a CATV mobile terminal (6) to receive a CATV service regardless of the service area of the CATV station where the user is located. When a vehicle (5) having a CATV mobile terminal (6) mounted thereon moves into a service area of a CATV station (3, 4), the CATV mobile terminal (6) is operated to transmit a log-in request to the CATV station (3, 4). The CATV station (3, 4) is operated to inquire about the user to the subscriber station (2), and the subscriber station (2) is operated to judge whether or not the user is authentic. Subscriber station (2) is operated to deliver common contents to the CATV mobile terminal (6) through the CATV station (3, 4) when it is judged that the user is authentic.