Disclosed is a device for automatically assembling a hinge, comprising a connecting piece module assembly device, an adjustment sheet module assembly device, a main body bracket module assembly device, and a finished hinge product assembly device, wherein the connecting piece module assembly device is used for assembling a connecting piece module; the adjustment sheet module assembly device is used for riveting an adjustment sheet module; the main body bracket module assembly device is used for assembling a main body bracket, a main body bracket bolt, and a screw into a main body bracket module; and the high finished product assembly device is used for assembling the connecting piece module, the adjustment sheet module, the main body bracket module, and other materials into a finished hinge product. The device for automatically assembling a hinge of the present invention is used for the automatic assembly of a hinge.