Abstract: A low-cost membrane cartridge and a low-cost method for producing a membrane cartridge, in which fatigue durability can be increased with a simple structure, are provided by focusing on a bonding position of the filtration membrane onto the filtration plate. The membrane cartridge includes a filtration membrane disposed on both faces of a filtration plate made of a thermoplastic resin, such that a joining portion provided at the periphery of the filtration membrane is joined to the filtration plate. At least an inner edge portion of the joining portion has a downward inclination with respect to the surface of the filtration plate inside of the inner edge portion at an angle in a range of 10 to 45 degrees toward an outer peripheral edge of the filtration membrane. The joining portion is pressed and welded using a heating plate or an ultrasonic horn having such an inclined surface.

Abstract: A low-cost membrane cartridge and a low-cost method for producing a membrane cartridge, in which fatigue durability can be increased with a simple structure, are provided by focusing on a bonding position of the filtration membrane onto the filtration plate. The membrane cartridge includes a filtration membrane disposed on both faces of a filtration plate made of a thermoplastic resin, such that a joining portion provided at the periphery of the filtration membrane is joined to the filtration plate. At least an inner edge portion of the joining portion has a downward inclination with respect to the surface of the filtration plate inside of the inner edge portion at an angle in a range of 10 to 45 degrees toward an outer peripheral edge of the filtration membrane. The joining portion is pressed and welded using a heating plate or an ultrasonic horn having such an inclined surface.