Provided is a hollow fiber membrane module designed to be substantially liquid-tight, to have high strength in welded joints and to be efficiently producible. The hollow fiber membrane module comprises a hollow fiber membrane bundle 4, a main body case 3 housing the hollow fiber membrane bundle 4, membrane fixing layers 5 for fixing the hollow fiber membrane bundle 4 to an inner wall in both ends of the main body case, and headers 8 and 9 attached to both open ends of the case and having an inlet 6 for a liquid to be treated and an outlet 7 for a liquid to be treated, respectively. In the hollow fiber membrane module, each of the headers 8 and 9 and the main body case 3 are ultrasonically welded around the entire circumference in at least two areas, a shear joint is used as a joint design for ultrasonic welding between an outer circumferential surface of the main body case and an inner surface of each header around the entire circumference, and a butt joint is used as a joint design for ultrasonic welding between an inner surface of each header and a corresponding end surface of the main body case around the entire circumference.
