The invention relates to an automatic capacitor assembling device, which comprises a machine frame, an element vibration disc, an element conveying track and a station disc are arranged on the machine frame, the discharging end of the element conveying track faces the station disc, and the automatic capacitor assembling device is characterized in that: a clamping device is arranged at the position, between the element conveying track and the station disc, of the machine frame; the clamping device comprises two sliding plates, an element positioning clamping jaw, an element clamping assembly and a sliding plate driving assembly, the two sliding plates are slidably connected with the top face of the machine frame, the element positioning clamping jaw is fixed to the side, away from the machine frame, of each sliding plate, and the element clamping assembly is arranged on the sliding plates and located at the discharging end of the element positioning clamping jaw, the sliding plate driving assembly is arranged in the machine frame, and the machine frame is provided with a batch feeding device above the element conveying track. According to the invention, the assembly accuracy of the element and the colloidal particles can be effectively improved, the subsequent assembly of the element is further ensured, the assembly stability of the capacitor is improved, and rapid production and manufacturing of the capacitor are realized.