To provide a container for treating cells, capable of preventing the breakage of a mesh member, even if the mesh member is clogged with living body tissues or cell chunk housed in a first space.

This container for treating cells 1 is provided, by equipping a first space 4 that houses living body tissue B and a treating liquid A for treating the tissue; a second space 5, equipped with a discharging port 9 sucked by a negative pressure; a filtering member 3, partitioning the first space 4 and the second space 5 and having many perforations inhibiting the passage of the living body tissue B and allowing the passage of the treating liquid A; and an air inlet part 6 for introducing air into the inside of the second space 5 and installing a relief valve 7 at the air inlet part 6, which is opened when the pressure in the second space 5 decreases to a pressure equal to or lower than a prescribed pressure.