A secured communication method for a V2X communication device is disclosed. The secured communication method for a V2X communication device comprises the steps of; receiving at least one message on the basis of V2X communication; extracting adaptive certificate pre-distribution (ACPD) target information when the at least one message includes the ACPD target information; pre-authenticating at least one short-term certificate acquired from the ACPD target information; collecting at least one pre-authenticated short-term certificate to be broadcasted at a specific predicted time at a specific predicted location; and broadcasting an ACPD group (ACPDG) message including the collected at least one pre-authenticated short-term certificate at the specific predicted location at the specific predicted time.