A V2X communication apparatus in a V2X communication system in a vehicle, wherein V2X communication means all communication corresponding to communication between a vehicle and a traffic signal apparatus, communication corresponding to communication between a vehicle and a user terminal and communication corresponding to communication between vehicles, the V2X communication apparatus comprising: a) a message transceiver adapted to receive a V2X communication message from an external vehicle surrounding the vehicle (101, 102, 103); b) a parameter calculator adapted to calculate a reliability verification parameter for verifying reliability of V2X data included in the V2X communication message; c) a reliability level decider adapted to check whether or not the reliability verification parameter exceeds a first reference value, whether or not the reliability verification parameter exceeds a second reference value, and whether or not the reliability verification parameter exceeds a third reference value, and to decide that a reliability level of the reliability verification parameter is a guidance level when the reliability verification parameter is less than the first reference value, to decide that the reliability level of the reliability verification parameter is a warning level when the reliability verification parameter is less than the second reference value, and to decide that the reliability level of the reliability verification parameter is a control level when the reliability verification parameter is less than the third reference value, d) a message generator adapted to generate the V2X data including the decided reliability level using the V2X communication message; and e) wherein the reliability level decider is adapted to set reliability of the first reliability level to be lowest among first, second and third reliability levels, and sets reliability of the third reliability level to be highest among the first, second and third reliability levels, wherein the first reliability level corresponds to the guidance level, the second reliability level corresponds to the warning level, and the third reliability level corresponds to the control level; and f) wherein the message transceiver is further configured to transmit the generated V2X data to an apparatus (120, 130, 140) of the V2X communication system in the vehicle (101, 102, 103), characterized in that the reliability verification parameter includes one or more of an information age, IA, parameter, a communication induced tracking error, CITE, parameter and a security parameter, wherein the CITE parameter and the security parameter are defined according to the Society of Automotive Engineers, SAE, J2945 standard, and wherein the IA is defined in the North America CAMP project. a) a message transceiver adapted to receive a V2X communication message from an external vehicle surrounding the vehicle (101, 102, 103); b) a parameter calculator adapted to calculate a reliability verification parameter for verifying reliability of V2X data included in the V2X communication message; c) a reliability level decider adapted to check whether or not the reliability verification parameter exceeds a first reference value, whether or not the reliability verification parameter exceeds a second reference value, and whether or not the reliability verification parameter exceeds a third reference value, and to decide that a reliability level of the reliability verification parameter is a guidance level when the reliability verification parameter is less than the first reference value, to decide that the reliability level of the reliability verification parameter is a warning level when the reliability verification parameter is less than the second reference value, and to decide that the reliability level of the reliability verification parameter is a control level when the reliability verification parameter is less than the third reference value, d) a message generator adapted to generate the V2X data including the decided reliability level using the V2X communication message; and e) wherein the reliability level decider is adapted to set reliability of the first reliability level to be lowest among first, second and third reliability levels, and sets reliability of the third reliability level to be highest among the first, second and third reliability levels, wherein the first reliability level corresponds to the guidance level, the second reliability level corresponds to the warning level, and the third reliability level corresponds to the control level; and f) wherein the message transceiver is further configured to transmit the generated V2X data to an apparatus (120, 130, 140) of the V2X communication system in the vehicle (101, 102, 103),