Abstract: The present invention provides a boiler structure, for use with a coffee machine and capable of automatic depressurization, comprising a lid, a sealing member, a boiler body, and a position-limiting support frame. The lid is configured with a water inlet pipe and a water outlet pipe and the water outlet pipe. The sealing member is fitted in an inner side of the lid and having a pressure relief ring, wherein the pressure relief ring has one or a plurality of pressure relief apertures at a pressure relief height. The boiler body is on one side of the lid, wherein the boiler body comprises a receiving space and an opening. The receiving space is in communication with the water inlet pipe and the water outlet pipe, and the opening is on one side of the receiving space. A heating device is on one side of the boiler body. The boiler body is movable downward by pressure while being heated by the heating device; and, when the opening of the boiler body reaches the pressure relief height, the pressure is relieved.