Blood treatment filter and blood treatment filter manufacturing method

A blood processing filter for removing undesirable components from liquid containing a blood component or blood, the filter comprising:

• a sheet-shaped filter element;
• and
• a container that includes an inlet-side container element and an outlet-side container element that are disposed to clamp the filter element, and has an internal space separated by the filter element into an inlet space and an outlet space,
• wherein the filter element includes a pair of filtering surfaces disposed on the inlet space side and the outlet space side, and an end surface along peripheries of the pair of filtering surfaces,
• the inlet-side container element and the outlet-side container element are provided with a gripper that clamps and compresses outer edge portions of the pair of filtering surfaces and adheres to the end surface with melt resin, and
• the container having a steam-permeable portion and other portion provided at a periphery of the steam-permeable portion, the steam-permeable portion and the other portion being made of a hard material and integrally formed with each other, and the steam-permeable portion being thinner than the other portion, and
• wherein the hard material is configured to inhibit deformation of the container during filtration.