Disclosed herein are an apparatus and method for achieving distributed consensus based on decentralized Byzantine fault tolerance. The apparatus may include one or more processors and an execution memory for storing at least one program that is executed by the one or more processors, wherein the program is configured to receive delegate request messages, each including a first transaction for requesting distributed consensus proposed by a client, and determine congress candidate nodes forming a consensus quorum, to be consensus nodes based on the delegate request messages, generate a prepare message that includes a second transaction for obtaining consent to results of determination of the consensus nodes, and send the prepare message to the consensus nodes, and receive commit messages, each including an electronic signature of a corresponding consensus node, from the respective consensus nodes, and broadcast a reply message indicative of results of verification of the electronic signatures.