PROBLEM TO BE SOLVED: To provide a chamber that can prevent the occurrence of foaming on a liquid level and the pulsation of the liquid level, and reduces a priming volume, in a so-called blood lower inflow and lower outflow type chamber.SOLUTION: A blood inflow pipe 3 and a blood outflow pipe 5 are installed in the lower part D side of a body 2, and the blood inflow pipe 3 has a blood flow inlet 3I and an opening part 3O. The blood inflow pipe 3 is inclined so as to go up from the blood flow inlet 3I to the direction of the opening part 3O from one side part S toward the other side part S side, and from the lower part D side toward the upper part U side, and is installed in the lower part D side of the body 2. When an angle formed by a horizontal line SL in the direction of one side part S to the other side S intersecting with a central line CL in the longitudinal direction of the blood inflow pipe 3 at an acute angle is determined as a blood inflow angle &thetas；, the blood inflow angle (&thetas；) is formed in 30° to 80°. The blood outflow pipe 5 is disposed substantially in parallel to the longitudinal direction of the body 2 from the opening part 5O of the upper part U side toward the blood flow outlet 5OU of the lower part D side.
