Provided are a method and device for building a security-based environment that uses an eUICC. A method of building a trust relationship in an eUICC environment includes transmitting, by a trust requesting object, a trust relationship requesting message including identification information and signature information of the trust requesting object to a trust verifying object, delivering, by the trust verifying object, the trust relationship requesting message to a trust relationship relay object and receiving trust information of the trust requesting object corresponding to the trust relationship requesting message from the trust relationship relay object, and verifying, by the trust verifying object, the signature information of the trust requesting object using the trust information of the trust requesting object.