A hollow fiber membrane blood purifying device (1) including a cylindrical container (2), a hollow fiber membrane bundle (3), a potting resin fixing portion (4) embedding and fixing the hollow fiber membrane bundle 3 at each end (2a, 2b) of the cylindrical container (2), headers (5) having nozzles (6), and ports (7) further has the structure in which each header (5) and the cylindrical container (2) are welded in at least two regions over the circumference. The inside face of the header (5) is in contact with a potting resin fixing portion cut face (4S) that is formed by cutting an outer side portion of the potting resin fixing portion (4) in the length direction of the cylindrical container (2) than the end face of each end (2a, 2b) of the cylindrical container (2), and the potting resin fixing portion cut face (4S) is in a compressively deformed state.一種中空絲膜型血液淨化器(1)，其具備：筒狀容器(2)；中空絲膜之束(3)；填充樹脂固定部(4)，其於筒狀容器(2)之兩端部(2a、2b)包埋固定中空絲膜之束(3)；集管(5)，其具有噴嘴(6)；及埠(7)；且進而具備使集管(5)與筒狀容器(2)遍及全周而於至少2個部位之區域熔接之構造。集管(5)之內側面相接於填充樹脂固定部(4)中之將較筒狀容器(2)之兩端部(2a、2b)之端面更靠該筒狀容器(2)的長度方向外側之部分切除之填充樹脂固定部切斷面(4S)，填充樹脂固定部切斷面(4S)成壓縮變形之狀態。
