| 摘要 |
A sheet-shaped filter membrane (22) is disposed on the surface of a filter plate (21) formed from a thermoplastic resin. A plurality of protruding parts (521, 522) provided in a heating plate (51) are pressed against the filter plate (21) from above the peripheral edges of the filter membrane (22), while making the timings by which the protruding parts (521, 522) abut against the filter membrane (22) differ, to thereby form a plurality of recessed joining parts (231, 232) with differing depths in the filter plate (21). At the recessed joining parts (231, 232), the filter membrane (22) is joined to the filter plate (21) by thermal fusing to seal the filter membrane (22) and the filter plate (21) together along the peripheral edges of the filter membrane (22). |
