The invention discloses an automatic assembly device for filters, which comprises a frame (1), a filter membrane feeding device (21) located on the frame (1), a bottom film feeding device (22), a double-layer film composite device (23), double-layer film stepping feeding device (24), filter membrane punching pick-up device (3), filter conveying device (4), filter welding device (5) and filter feeding device (6 ), the above-mentioned devices work together to complete the assembly of the filter. Compared with the prior art, the filter automatic assembly device of the present invention can automatically assemble the filter, punching, film suction, and assembly in one go, with a high degree of automation, prevents the deviation of the suction film, and has high product assembly accuracy. Suction, the film obtained is more complete and docile.