Provided is a blood treatment device configured, without impairing the original function of obstruction members, in such a manner that air can easily and quickly flows in the direction of the dialysis solution outlet port of a housing (2) without staying in the space of the housing (2). In a view in the longitudinal direction of the housing (2), obstruction members (11) having a substantially circular cylindrical shape are disposed at the position where a dialysis solution inlet port (7.1) is formed and/or at the position where a dialysis solution outlet port (7.2) is formed. The obstruction members (11) each have an opening (11OP) which is formed in at least one place facing the direction of a side section (S) and which extends in the longitudinal (L) direction. Each of the openings (11O) has a proximal end opening (11OPE) having a smaller width and also has a distal end opening (11ODE) having a larger width. The distal end opening (11ODE) and/or the proximal end opening (11OPE) is configured so that the distal end opening (11ODE) and/or the proximal end opening (11OPE) has rounded sections (R) formed so as to face the directions of both side sections (S), and so that the opening degree of the opening(11OPE, 11ODE) changes gradually.本發明係提供一種不損及原本當作為障礙構件之功能且空氣不滯留於殼體2之空間內而容易迅速地朝殼體之透析液進出埠出口方向排出之血液處理裝置。本發明之血液處理裝置係從殼體2之長邊方向觀察，於形成有透析液進出埠入口7.1及/或透析液進出埠出口7.2之位置，配置有大致呈圓筒狀之障礙構件(11)，且該障礙構件11於側部S方向之至少一個部位以沿長邊L方向之方式形成開口部11OP。而且，該開口部11O具有寬度較窄之基端側開口部11OPE、及寬度較寬之末端側開口部11ODE。該末端側開口部11ODE及/或基端側開口部11OPE係於兩側部S方向上形成曲線部R，且以其開口度逐漸變化之方式所構成。
