Disclosed is a digital signature service system and method based on a hash function in which a main agent, who requires the generation of a digital signature, does not personally generate the digital signature, and wherein digital signatures may be simultaneously and stably generated for large-scale data such as multiple electronic documents and digital data using a hash function and a hash tree, which are known as a simple and secure method, to guarantee the integrity of the data in a digital signature-based structure based on a server.